Definitions for first-degree burn. Here are all the possible meanings and translations of the word first-degree burn. Princeton's WordNet(0.00 / 0 votes)Rate this definition: first-degree burn(noun) burn causing redness of the skin surface. first-degree burn(Noun) A mild burn that causes redness of the skin but no blistering. Chaldean Numerology. The numerical value of first-degree burn in Chaldean Numerology is: 3.