Cases of word usage

1) any animal of a group having jointed legs, a segmented body and a hard external skeleton, such as a crab, spider, beetle or centipede (arthropod)

2) the property of matter by which it remains in a state of rest or, if it is in motion, continues in the same direction and in a straight line unless it is acted on by an external force (inertia)

3) either of the two external openings into the nose (nostril)

4) an external boundary or surface (periphery)

5) the passage in a female mammal from the external genital organs to the womb (vagina)