autoAlpha — shorthand property that tweens opacity and toggles visibility:hidden at 0, avoiding pointer-events on invisible elements (Ch GSAP Core).
ease — a function controlling the rate of change of a tween over time (e.g. "power2.out", "elastic", "none"); GSAP ships dozens of built-in eases and supports custom ones via CustomEase.
Flip — plugin that records element state (position/size/rotation/opacity), applies a DOM change, then animates from the old state to the new one ("First, Last, Invert, Play").
force3D — GSAP config option that controls whether transforms use translate3d() (GPU-accelerated) vs translate(); "auto" (default) toggles based on the property being animated.
function-based value — passing a function instead of a static value/string to a tween property; GSAP calls it per-target, receiving (index, target, targets), useful for staggered or per-element variation.
gsap.context() — scopes selectors and cleanup to a DOM node; context.revert() undoes every tween/ScrollTrigger created inside it — the standard cleanup pattern in React/Vue.
gsap.matchMedia() — GSAP's responsive helper: register animations per media-query breakpoint; automatically reverts and re-runs the right block when the breakpoint changes.
gsap.quickSetter() — returns a function that sets a property directly (bypassing the tween engine) for extremely fast, repeated updates (e.g. mouse-follow effects).
gsap.quickTo() — returns a reusable tween function bound to a specific property; calling it repeatedly with new values retargets the existing tween instead of creating a new one — the recommended pattern for drag/mousemove-driven animation.
gsap.registerPlugin() — makes a plugin's properties/methods available to gsap.to()/timeline(); required once per session before using any plugin (CSS/ScrollTrigger/Draggable/etc.).
GSDevTools — visual scrubber/inspector UI for debugging timelines in the browser.
Inertia (InertiaPlugin) — physics-based plugin that animates a property to a natural stop based on velocity, with optional snapping.
invalidateOnRefresh — ScrollTrigger option: recalculates tween start/end values on each refresh() (e.g. window resize), needed when animated values depend on element dimensions.
keyframes — an array (or object) of property sets on a single tween, animating through each step in sequence without creating a full timeline.
label — a named marker on a timeline (tl.addLabel("start")) used to sequence, jump to, or reference a point in time instead of a raw number.
MorphSVGPlugin — morphs one SVG path's shape into another, matching points automatically or via manual type:"rotational" control.
MotionPathPlugin — animates a target along an SVG path (motionPath: "#path"), auto-rotating to match the path's direction if autoRotate is set.
Observer — low-level plugin that normalizes wheel/touch/pointer/scroll events into simple callbacks (onUp/onDown/onDrag), the basis for many custom scroll/swipe interactions (and ScrollTrigger internally).
pin (ScrollTrigger) — freezes an element in the viewport for the duration of a scroll-triggered animation, unpinning at end.
position parameter — the second argument to tl.to()/tl.set()/etc. inside a timeline (e.g. "+=0.5", "<", "myLabel") controlling where in time the tween is inserted relative to the previous tween or a label.
scrub (ScrollTrigger) — ties a timeline's playhead directly to scroll position instead of playing independently; true for 1:1, a number for a smoothing delay in seconds.
SplitText — splits text into chars/words/lines <div>s (or custom elements) for per-character/word/line animation; requires a Club GreenSock (now free) license for production reverts on resize.
stagger — offsets the start time of each target in a multi-target tween; accepts a number (seconds between each) or an object ({each, from, grid, ease}) for advanced patterns.
timeline — a container (gsap.timeline()) that sequences and nests tweens with a single controllable playhead; the primary tool for choreographing multi-step animations.
toggleActions (ScrollTrigger) — four keywords (play/pause/resume/reverse/restart/reset/complete/none) controlling what happens on enter/leave/enter-back/leave-back of the trigger viewport.
tween — the core animation unit (gsap.to()/.from()/.fromTo()/.set()) that interpolates one or more properties of one or more targets over time.
units — GSAP infers CSS units automatically from the current computed value; relative values ("+=100", "*=2") and unit-less numbers are also supported per-property.