In the oracle bone and bronze scripts, it was an ideogrammic compound (會意): 丵(“tool for digging”) + 土(“earth”) + 又(“hand”). The original meaning of the character is unclear, but it may be “to develop (land)”. It was later borrowed for “to reply”. Compare 封, 邦.
In the seal script, 又 has become the related 寸. Shuowen has two seal script forms for this character: 𡭊 (main form) and 對 (alternative form). The main form, which has a 口 (“mouth”), was probably created to specialize the character to signify “to reply”, but this form was not inherited in later scripts. Shuowen interprets the latter form (shown above) as a form that Emperor Wen of Han created by replacing 口 with 士 (“soldier; warrior”) because many of the replies were untruthful (just lip service), but it is more likely that 士 is a corruption of 土.