The term 'Word of Regret' is used to describe words that express sorrow or regret. The three crossword solutions for this term are ALAS (4 letters), SORRY (5 letters), and ALACK (5 letters). ALAS is an interjection used to express sorrow, regret, or dismay, while SORRY is an adjective used to express regret or apology. ALACK is an archaic interjection used to express sorrow or regret. All three words can be used to express regret or sorrow in different contexts.