to make larger, greater, or stronger; enlarge; extend.

to expand in stating or describing, as by details or illustrations; clarify by expanding.

Electricity . to increase the amplitude of; cause amplification in.

Archaic . to exaggerate.

to discourse at length; expatiate or expand one's remarks, speech, etc. (usually fol. by on )

The preacher amplified on the theme of brotherly love.

verb

abridge , compress , condense , contract , curtail , decrease , lessen , reduce , shorten , summarize

verb

add , augment , beef up * , boost , build up , deepen , develop , elaborate , enlarge , exaggerate , expand , expatiate , extend , flesh out , heighten , hike up , inflate , intensify , jack up , lengthen , magnify , pad , pyramid , raise , soup up , strengthen , stretch , supplement , swell , up , widen , aggrandize , build , burgeon , escalate , grow , mount , multiply , proliferate , rise , run up , snowball , soar , upsurge , wax , dilate , labor , increase