表面外膜 biǎomiànwàimó surface coat Origin Definitions Defs Strokes Stroke Words Sentences Sents 表面 biǎomiàn noun surface the outermost layer of an object; face; outside外膜 wàimó outer membrane A layer of loose connective tissue forming the outermost layer of an organ, such as the heart or blood vessels; often used in contrast to the 内膜 nèimó