The word “render” is most often used in the context of graphics (2D and 3D) and means creating something visual from the abstract. A “render” in that context refers to the creation of an individual frame on the screen - and many frames comprise a video or animation.
However, in the context of React, “render” more typically means taking the JSX template of a component and displaying it on screen, since the template specifies the “visual” part of the component. You can kinda think of it like “render this component specified by this template” which basically means to put it on the screen in a specific location.