1) a collection of thick yellowish white liquid (called pus) formed in a diseased part of the body (abscess)

2) a word formed from the (usually) first letters of other words, e.g. NATO (acronym)

3) a ball formed of liquid and containing air or gas, e.g. one that forms in boiling water (bubble)

4) a semi-solid lump formed from liquid, especially blood (clot)

5) an idea, plan etc that is formed in the mind (conception)

6) an origin; a statement of how a world was formed and how it has changed (derivation)

7) an organic chemical substance formed in plants and animals, able to cause chemical changes without being changed itself (enzyme)

8) a white mass of small air bubbles as formed in or on a liquid (foam)

9) a mass of ice, formed by snow on mountains, moving slowly along a valley (glacier)

10) a narrow channel cut or formed by rainwater, e.g. on a hillside, or for carrying water away from a building (gully)