Cases of word usage

1) a kind of shellfish with eight legs and two claws, bluish-black before and pink after being boiled (lobster)

2) a flat figure with eight sides and angles (octagon)

3) an interval of eight notes between two notes so that the first has a pitch double the value of the other; the first eight lines of a sonnet; verse of eight lines (octave)

4) (a piece of music for) eight singers or players (octet)

5) a sea-animal with a soft body and eight arms (tentacles) with suckers (octopus)

6) the Scorpion, eight sign of the zodiac (scorpio)

7) a kind of creature with eight legs that can make a net (web) to catch insects (spider)