Short, exact definitions of the terms you meet when planning, publishing and measuring social media. Each entry has a formula or example and links to a free tool that does the job.
Engagement rate
Engagement rate is the percentage of people who interacted with a post (liked, commented, shared, saved or clicked) out of the people who saw it or follow the account.
Reach
Reach is the number of unique people who saw a post or account at least once in a given period.
Impressions
Impressions are the total number of times a post was displayed on screen, counting repeat views by the same person.
Click-through rate (CTR)
Click-through rate is the percentage of people who clicked a link in a post out of everyone who saw it.
Save rate
Save rate is the percentage of people who saved (bookmarked) a post out of the people who saw it.
Amplification rate
Amplification rate is the number of shares a post receives relative to your follower count, showing how often your audience passes your content on to their own networks.
Conversion rate
Conversion rate is the percentage of people who completed a goal, such as a purchase, sign-up or download, out of everyone who clicked or visited from a given source.
Cost per click (CPC)
Cost per click (CPC) is the amount an advertiser pays for each click on an ad, either as the price set in a pay-per-click auction or as total spend divided by clicks.
CPM (cost per mille)
CPM, or cost per mille, is the price an advertiser pays for 1,000 impressions of an ad, used both as a way to buy ads and as a metric for comparing campaign costs.
Follower growth rate
Follower growth rate is the percentage change in an account’s follower count over a set period, usually a month, measured against the count at the start of that period.
Organic reach
Organic reach is the number of unique people who saw a post or account through unpaid distribution (feeds, search, shares and recommendations), excluding anyone reached through ads.
Share of voice (SOV)
Share of voice is the percentage of all mentions, conversations or ad visibility in a market that belongs to your brand, compared with the competitors you track.
Social media KPI
A social media KPI (key performance indicator) is a metric you have chosen to track against a specific business goal, with a target and a time frame, to show whether your social media work is succeeding.
Social media ROI
Social media ROI (return on investment) is the value earned from social media activity, minus what it cost, expressed as a percentage of that cost.
Vanity metrics
Vanity metrics are numbers that are easy to grow and look impressive, such as total followers, likes or views, but that do not show whether social media is meeting a business goal or tell you what to do next.
Video completion rate
Video completion rate is the percentage of views in which a video was watched all the way to the end.
Virality rate
Virality rate is the percentage of impressions on a post that led to a share, showing how likely people who saw the post were to pass it on.
Watch time
Watch time is the total amount of time viewers spent watching a video or channel, usually reported in minutes or hours.
Carousel post
A carousel post is a single post containing several images or videos that people swipe through, one slide at a time.
Aspect ratio
Aspect ratio is the proportional relationship between an image or video’s width and height, written as width:height (for example 4:5 or 16:9).
Safe zone
A safe zone is the part of an image or video frame that stays visible after the app overlays its buttons, captions and profile details.
Character limit
A character limit is the maximum number of characters a platform accepts in a post, caption or field, including spaces, emojis and links.
Alt text
Alt text is a short written description of an image that screen readers read aloud, so people who cannot see the image still get its meaning.
Call to action
A call to action (CTA) is the part of a post or ad that tells people the one specific thing to do next, such as comment, save, visit a link, sign up or buy.
Collab post
A collab post is a single Instagram post or reel co-authored by two or more accounts, which appears on every collaborator’s profile and is shown to each of their audiences.
Company Page
A Company Page is the official presence of an organisation on a social network, such as a LinkedIn Page or a Facebook Page, run by admins on the organisation’s behalf rather than by one person’s profile.
Dark post
A dark post is a sponsored post that is shown only to the audience an advertiser targets and never appears as a regular post on the brand’s own page or profile.
Hashtag
A hashtag is a word or phrase written after the # symbol, with no spaces, that turns into a clickable link grouping public posts on the same topic.
Hook
A hook is the opening of a post (the first line of text, the first slide or the first seconds of a video) designed to make people stop scrolling and keep reading or watching.
Link in bio
“Link in bio” is a phrase used in a post to send people to the clickable link on the account’s profile, used on apps such as Instagram and TikTok where the profile is the main place a link can go.
Pinned post
A pinned post is a post you fix to the top of your profile or page so it stays above your newer posts and is the first thing visitors see.
Reels
Reels are short, vertical, full-screen videos on Instagram and Facebook that play with sound and are recommended to people who do not follow the account, as well as to followers.
Short-form video
Short-form video is vertical video, usually under three minutes, made to be watched full screen on a phone in a feed that plays the next clip automatically, such as TikTok, Instagram Reels and YouTube Shorts.
Stories
Stories are full-screen, vertical photos and videos that appear at the top of the app and disappear after 24 hours, unless the account saves them to a profile Highlight.
Story Highlights
Story Highlights are collections of past Instagram Stories saved to your profile, where they stay visible after the usual 24 hours until you remove them.
Thread
A thread is a series of posts by the same account, each published as a reply to the one before, so readers can follow a longer idea in order beyond a single post’s character limit.
User-generated content
User-generated content (UGC) is any content about a brand made by people outside it, such as customers’ photos, videos, reviews and posts, rather than by the brand itself.
UTM parameters
UTM parameters are short tags added to the end of a URL (utm_source, utm_medium, utm_campaign and more) that tell analytics tools like Google Analytics where a visit came from.
First comment
The first comment is a comment the author posts on their own post straight after publishing, usually to hold a link, extra hashtags or a call to action.
Best time to post
The best time to post is the day and hour when your own followers are most likely to be online and engage, which differs by platform, audience and time zone.
Content calendar
A content calendar is a shared schedule of what will be posted, on which platforms and at what time, usually planned weeks ahead.
Cross-posting
Cross-posting is publishing the same piece of content to more than one social network, either unchanged or adapted for each one.
Content repurposing
Content repurposing is turning one piece of content, such as a blog post, video or talk, into several new pieces in different formats for different platforms.
Social media scheduler
A social media scheduler is software that lets you write posts in advance and publishes them automatically to your social accounts at the times you choose.
MCP server
An MCP server is a service that exposes an app’s actions as tools that AI assistants can call, using the open Model Context Protocol (MCP).
AI agent
An AI agent is an AI model that can take actions through connected tools, such as creating a draft, uploading an image or scheduling a post, to complete a goal you give it, rather than only replying with text.
Approval workflow
A social media approval workflow is the set of review steps a post must pass, such as a manager or client sign-off, before it can be scheduled or published.
Batch content creation
Batch content creation is producing many social media posts in one focused session, such as a week or a month at a time, instead of writing each post on the day it goes out.
Brand voice
Brand voice is the consistent personality a brand shows in its writing, such as friendly, expert or playful, so that its posts sound like the same company on every platform.
Bulk scheduling
Bulk scheduling is loading many social media posts into a scheduling tool at once, usually from a spreadsheet or CSV file, with each post’s text, date and time, instead of scheduling them one by one.
Community management
Community management is the work of building and looking after a brand’s audience on social media by replying to comments and messages, moderating conversations and starting discussions, so followers feel heard and keep coming back.
Content pillars
Content pillars are the small set of recurring themes, usually three to five, that a brand’s social media content is built around, each tied to what the audience cares about and what the business wants to be known for.
Employee advocacy
Employee advocacy is when a company’s staff share its news, content and their own expertise on their personal social media accounts, so the brand reaches their networks through people those networks already trust.
Evergreen content
Evergreen content is content that stays relevant and useful for months or years after it is published, because it does not depend on news, trends or dates.
Influencer marketing
Influencer marketing is a brand partnering with creators, by paying them or giving them products, to promote the brand to the creator’s own audience in the creator’s own voice.
Social commerce
Social commerce is selling products directly through social media platforms, where people can discover a product in a post or video and view details or buy it without searching for it elsewhere.
Social listening
Social listening is tracking public online conversations about your brand, competitors, products and industry, then analysing them to guide content, product and customer decisions.
Social media algorithm
A social media algorithm is the set of ranking systems a network uses to decide which posts each person sees, and in what order, based on predictions of what that person is likely to engage with.
Social media API
A social media API is a set of official endpoints a network (or a scheduling tool) offers so software can publish posts, upload media and read analytics on an account without anyone using the app by hand.
Social media audit
A social media audit is a structured review of all of a brand’s social accounts, covering profiles, content and results, to find what is working, what is not and what to change.
Postprism schedules your posts to 6 networks from one calendar and shows the metrics that matter for each one.