What's the meaning of 登假 in old daoist scriptures like Zhuang Zi?
《康熙字典》
又《集韻》《正韻》與格同，至也。《易·萃卦》王假有廟。


from Kangxi Dicitionary: the 13th meaning of 假

It pronounces as 格, means 'arrive'. Example sentence from Yi Cuigua: The King arrives at the ancestral temple.

^ref