Adapt - adopt

Adapt and adopt are two words sometimes confused.

• To adapt, as a transitive verb, means: to alter something for a different purpose. 'People have adapted lawn-mower engines to propel go-carts and micro-light aircraft.' The noun is adaptation. It has two '-t-'s. Adaption should be regarded as an error. The adjective, nevertheless, is adaptive. (A form, 'adaptative', was current in the nineteenth century, but rare even then: it is now obsolete.)
• To adopt is, in its most basic sense, to take over someone else's child as one's own. (The children most usually adopted are orphans.) Other meanings follow this idea - that one chooses (or opts) to take over what is someone else's, e.g., policy, theory or proposal. The noun (like 'option') is adoption. It has only one '-t-', unlike 'adaptation'. The adjective, more reasonably this time, is adoptive.
  • At times, students can be unsure whether to use 'adopted from' or 'adapted from', when referencing a diagram, chart or table etc which they have taken from another source. Only use 'adopted' when it is copied faithfully, with no changes - or indeed, in this case, simply give the reference. If there is any change, for example if you have re-drawn the original, made (and marked) some omissions or updated some data, then you should say 'adapted from', with the full original reference. If in doubt, it is permissible to use the more ambiguous 'after [the reference]'.

There is also an adjective, also used as a noun, adept. Its basic meaning is 'expert'.