The crossword solution for the term 'A AS IN 'AUTUMN'' is 'SCHWA, ' which is a five-letter word. The schwa is a linguistic term used to refer to an unstressed and toneless neutral vowel sound in some languages, such as English. It is represented by the symbol ə and is the most common vowel sound in the English language. It is also known as the 'mid-central vowel' and is typically found in unstressed syllables.