1) the process, result, of adding (addition)

2) the total obtained by adding amounts together (aggregate)

3) to improve (something) by changing the words, adding information etc (amend)

4) to make (something) dirty, impure or diseased (by touching or adding something impure) (contaminate)

5) to make (a liquid or colour) weaker or thinner (by adding water or other liquid) (dilute)

6) to join (parts) into a whole; complete (something) by adding parts (integrate)

7) one of a series of numbers set out in tables which make it possible to work our problems in multiplication and division by adding and subtracting (logarithm)

8) to make (something) stronger by adding or supplying more people or material (reinforce)

9) to improve (a photograph), painting etc) by adding a little paint with a brush etc (retouch)

10) of the highest degree or quality; a form of an adjective or adverb expressing the highest degree (usually made by adding '-est' or with 'most'), such as 'happiest', 'longest', 'worst', 'most likely' (superlative)