点 (diǎn) — (noun) dot, point, drop; o'clock; (classifier) for small amounts or items; for abstract points (ideas, opinions)

Here 点 is a noun meaning 'o'clock / a point in time' and a classifier for small amounts (a bit of water, a little money). Don't confuse it with 时, which is the standalone noun 'hour' used after a number. 一点 also means 'a little' in quantity.

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

This origin belongs to the traditional form 點; 点 is its simplified writing.

The traditional form 點 pairs 黑 (black) with 占 for its sound; the simplified 点 is a later abbreviation.