The term 'Alphabet Quartet' refers to a set of eight words, each consisting of four letters, that form a sequence from the first four letters of the alphabet (STU) to the last four letters of the alphabet (STUV). The crossword solutions for this term are STU (3 letters), CDEF (4 letters), EFGH (4 letters), LMNO (4 letters), MNOP (4 letters), QRST (4 letters), RSTU (4 letters), and STUV (4 letters). Together, these eight words form a complete sequence of the alphabet, from start to finish.