What is the meaning of þem?

Third-person plural accusative pronoun: them

themselves

Brink, Daniel (1992) “Variation between <þ-> and <t-> in the Ormulum”, in Irmengard Rauch, Gerald F. Carr and Robert L. Kyes, editors, On Germanic Linguistics: Issues and Methods (Trends in Linguistics. Studies and Monographs; 68), De Gruyter Mouton, →DOI, →ISBN, pages 21-35.

Thurber, Beverly A. (2011 February 15) “Voicing of Initial Interdental Fricatives in Early Middle English Function Words”, in Journal of Germanic Linguistics, volume 23, number 1, Cambridge University Press, →DOI, pages 65-81.

theim, pron.”, in MED Online, Ann Arbor, Mich.: University of Michigan, 2007.

Alternative form of þan (the, that, this)

Alternative form of teme (family, tribe)

Alternative form of temen (to produce offspring)

Source: wiktionary.org