Search Result for "microseism": 
Wordnet 3.0

NOUN (1)

1. a small earthquake;
[syn: tremor, earth tremor, microseism]

The Collaborative International Dictionary of English v.0.48:

Microseism \Mi"cro*seism\, n. [Micro- + Gr. ? an earthquake, fr. ? to shake.] A feeble earth tremor not directly perceptible, but detected only by means of specially constructed apparatus. -- Mi`cro*seis"mic, Mi`cro*seis"mic*al, a. [Webster 1913 Suppl.]
WordNet (r) 3.0 (2006):

microseism n 1: a small earthquake [syn: tremor, earth tremor, microseism]