a small spot or mark, typically (√); esp one used to mark something as correct, to check an item on a list, etc: compare cross¹ (1b)

a light rhythmic audible tap or beat, or a series of such sounds

Brit, informal a moment or second

on the stock market, the smallest amount by which the price of a stock, etc can fluctuate

to mark (something) with a written tick

(often + off) to mark or count (something) by ticks, or as if by ticks

I seat in the taxi watching the meter ticking off the fare

to make the sound of a tick

informal to function or behave characteristically

I'd like to know what makes him tick

a bloodsucking arachnid that feeds on warm-blooded animals and often transmits infectious diseases

informal a wingless bloodsucking insect, e.g. one that is parasitic on sheep

a strong coarse fabric case of a mattress, pillow, or bolster

= ticking