lower case -
The minuscule or small letters a, b, c, as opposed to the uppercase or capital letters, A, B, C.
Wikipedia
Lower case (also lower-case or lowercase), minuscule, or small letters are the smaller form of letters, as opposed to upper case or capital letters, as used in European alphabets. For example, the letter "a" is lower case while the letter "A" is upper case. Originally alphabets were written entirely in capital letters, spaced between well-defined upper and lower bounds.
