Noun
minimal pair (plural minimal pairs)
(phonology) A pair of words differing by only one phonetic segment or suprasegment, used to prove the validity of a proposed phoneme, toneme, or chroneme.
"Beach and bitch" and "bun and ban" are examples of minimal pairs.
Phonemic differentiation may vary between different dialects of a language, so that a particular minimal pair in one accent is a pair of homophones in another. Source: Internet
It is virtually impossible to find a minimal pair to distinguish English main from main, yet it seems uncontroversial to claim that the two consonants are distinct phonemes. Source: Internet
Japanese also prominently features geminate consonants, such as in the minimal pair 来た kita 'came' and 切った kitta 'cut'. Source: Internet