Sutra:
98. ayanamenRathu - ivaRRukku AsrayamenRapadi.

Meaning:
"ayanam" means He is the refuge of these (nitya vaSthus).

Sri PBA Swami's Sarartha Deepikai:
Here on the meaning of ayana term is explained.

ayanam stands for Asrayam - that is, Narayana is the refuge for the nAras.