[ 'asɪm(p)təʊt ]
■ noun a straight line that continually approaches a given curve but does not meet it at any finite distance.
Derivatives
asymptotic ˌasɪm(p)'tɒtɪk adjective
asymptotically adverb
Origin
C17: from mod. L. asymptota (linea) '(line) not meeting', from Gk asumptōtos 'not falling together'.