definition of
tick

[1] #1 tick n. [ticking] a metallic tapping sound; "he counted the ticks of the clock". wn

[2] #2 tick v. [click] make a clicking or ticking sound; "The clock ticked away". wn

[3] #3 tick n. any of two families of small parasitic arachnids with barbed proboscis; feed on blood of warm-blooded animals. wn

[4] #4 tick v. [ticktock, ticktack, beat] make a sound like a clock or a timer; "the clocks were ticking"; "the grandfather clock beat midnight". wn

[5] #5 tick n. [check mark, check] a mark indicating that something has been noted or completed etc.; "as he called the role he put a check mark by each student's name". wn