British capacity unit bri·tish·ca·pacityunit uncommon noun 1. a unit of measure for capacity officially adopted in the British Imperial System; British units are both dry and wet SynonymsBritish capacity unitImperial capacity unit Related words Broader terms liquid unitdry unit Narrower terms barrelminimfluidramfluidouncegillpintquartgallon WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.