Cases of word usage

1) an instrument used by dentists (when pulling out teeth) and by doctors for gripping things (e.g. the head of the baby when being withdrawn from mother's womb) (forceps)

2) an instrument used for gripping things, pulling nails out of wood etc (pincers)

3) a kind of tool used for gripping and turning nuts on screws, bolts etc (US = wrench) (spanner)

4) a sudden and violent twist or pull; a kind of tool for gripping and turning nuts, bolts etc (wrench)