| noun | a component that is added to something to improve it “the addition of a bathroom was a major improvement” |
| noun | the act of adding one thing to another “the addition of flowers created a pleasing effect” |
| noun | a quantity that is added “there was an addition to property taxes this year” |
| noun | something added to what you already have “the librarian shelved the new accessions” |
| noun | a suburban area laid out in streets and lots for a future residential area |
| noun | the arithmetic operation of summing; calculating the sum of two or more numbers “the summation of four and three gives seven” |
| add | verb | bestow a quality on |
| add on | verb | make an addition |
| improve | verb | to make better |
| increase | verb | make bigger or more |
| summational | adjective | of or relating to a summation or produced by summation |
| sum | verb | determine the sum of |