It's explained right in the linked Wikipedia page:
> The term "memoization" was coined by Donald Michie in 1968[3] and is derived from the Latin word "memorandum" ("to be remembered"), usually truncated as "memo" in American English, and thus carries the meaning of "turning [the results of] a function into something to be remembered". While "memoization" might be confused with "memorization" (because they are etymological cognates), "memoization" has a specialized meaning in computing.
> The term "memoization" was coined by Donald Michie in 1968[3] and is derived from the Latin word "memorandum" ("to be remembered"), usually truncated as "memo" in American English, and thus carries the meaning of "turning [the results of] a function into something to be remembered". While "memoization" might be confused with "memorization" (because they are etymological cognates), "memoization" has a specialized meaning in computing.