I reckon that's right, 3 letters
Backwoods affirmative, 3 letters
Consent, in an oater, 3 letters
Counterpart of 'nope', 3 letters
Cowboy confirmation, 3 letters
Cowboy's affirmative, 3 letters
Cowboy's positive response, 3 letters
Dogpatch affirmative, 3 letters
Gary Cooper affirmative, 3 letters
Informal affirmative, 3 letters
Response from Gary Cooper, 3 letters
Slang for affirmative, 3 letters
Slangy confirmation, 3 letters
Cowboy affirmatives, 4 letters
Informal affirmatives, 4 letters
Nonchalant affirmatives, 4 letters
O.K.'s from the O.K. Corral?, 4 letters