increment

Concise Oxford English Dictionary © 2008 Oxford University Press:
increment /ˈɪŋkrɪm(ə)nt/

▶noun

• 1 an increase or addition, especially one of a series on a fixed scale.

  ■ a regular increase in salary on such a scale.

• 2 Mathematics a small positive or negative change in a variable quantity or function.

– derivatives
incremental adjective,
incrementally adverb.

– origin ME: from L. incrementum, from the stem of increscere (see increase).