1. any of two families of small parasitic arachnids with barbed proboscisfeed on blood of warm-blooded animals
2. a light mattress
3. a mark indicating that something has been noted or completed etc.
e.g. as he called the role he put a check mark by each student's name
Synonym: check markcheck
4. a metallic tapping sound
e.g. he counted the ticks of the clock
Synonym: ticking
💡 关键要点
1. any of two families of small parasitic arachnids with barbed proboscisfeed on blood of warm-blooded animals 2. a light mattress 3. a mark indicating that something has been noted or compl