"that which there is when people obtain land," "i.e. a grant of land, a landholding"
(see attestations)
John Bierhorst provides the definitions quoted in the Principal English Translation field. He points to the verb tlalmecehua and the noun tlalmacehalli (from the Codex Chimalpopoca).
The Codex Quetzalecatzin repeatedly uses "tlalli macehualli" next to various lords on thrones. This expression seems tied to tlalmacehualli and to the grants of land that town founders (tlalmaceuhqueh) received in their communities. (SW)
All of these terms may also relate to the term tlalmaceuhqui, land deserver, land winner, town founder, which became especially common in the late Spanish colonial era, when competition over land heightened. (SW)