the.com/indent

means To set text or a line in from the margin — or, as a noun, that inward notch or gap itself.

from From Latin 'dens' (tooth), via medieval Latin 'indentare' — literally 'to furnish with teeth.' It first described cutting a document's edge into jagged, tooth-like notches so two copies (say, a contract torn in half) could later be matched up to prove they belonged together. The 'fitting teeth together' sense faded, but the notch survived — eventually flattening into the polite little gap at the start of a paragraph.