[ ɪ'ratɪk ]
■ adjective not even or regular in pattern or movement.
■ noun (also ~ block or boulder ) Geology a large rock that differs from the surrounding rock, brought from a distance by glacial action.
Derivatives
~ally adverb
~ism noun
Origin
ME: from OFr. erratique , from L. ~us , from errare 'to stray, err'.