illăbōro (inl-), āre, v. n. [in-laboro],
to work upon , labor at : illaborare domibus (i. e. aedificandis), to work at building houses , Tac. G. 46 fin.
in-labōrō (ill-) —, —, āre, to work upon, work at: domibus (i. e. aedificandis), Ta. ...
An Elementary Latin Dictionary