The crossword solutions for the term 'Oh, Heck!' are 'DARN' and 'Rats'. Both of these terms are exclamations of surprise or disappointment. They are often used as a milder alternative to stronger swear words. DARN is derived from the Middle English word 'darnen', which means to mend or repair something with a needle and thread. Rats is an abbreviation of the phrase 'rats in the belfry', which is an idiom meaning someone is acting crazy or irrational.