Baseline

The term baseline can have several meanings depending on the context. It may refer to:

Baseline (compatibility)
Baseline identifies the availability of web platform features across popular browsers, including APIs, CSS properties, and JavaScript syntax. Baseline describes web features as being either widely available or newly available. Features that do not meet the Baseline criteria are said to have limited availability.
Baseline (typography)
A baseline is an imaginary line along the inline axis of a line box along which individual glyphs of text are aligned. Baselines guide the design of glyphs in a font and the alignment of glyphs from different fonts or font sizes when typesetting.