The term 'PUB BARREL' is a combination of two words, 'PUB' and 'BARREL'. PUB is a shortened form of the word 'public house', which is a type of drinking establishment found in many countries. A BARREL is a large cylindrical container used to store and transport liquids, such as beer or wine. Therefore, a PUB BARREL is a large BARREL used to store and transport beer or wine for a PUB. The crossword solution for this term is 'KEG', which is a type of BARREL used to store and transport beer.