What is the meaning of Halftone?

Synonym of semitone, half the interval between two notes on a scale.

A picture made by using the process of half-toning.

An intermediate or middle tone in a painting, engraving, photograph, etc.; a middle tint, neither very dark nor very light.

To reproduce a photograph or other continuous tone image by the use of dots of various sizes.

Source: wiktionary.org