Correct spelling, explanation: minute is the correct form and it comes from Latin minuta. Mynute is a mistaken form and it probably emerged from the pronunciation /ˈmɪnɪt/, in which, especially in American English, we can hear y sound more than i. However minute is the correct form due to its Latin origin.

Definition of minute:
noun, sixty seconds; an indefinite short moment in time
We start our lecture in one minute.
Wait for me! I will be ready in a minute.

Incorrect spelling, explanation: this form is incorrect, and the correct spelling is minute. This is because the Latin origin of this word is also spelled with i – minuta. Mynute is a mistake caused probably by pronunciation, in which we cannot hear clear i, but some sound between i and y; /ɪ/ in the phonetic alphabet (like, for example, in the word definite). Because of its origin, though, the correct form is minute.

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling