As in skandha स्कन्ध
歌字門，入諸法聚不可得故
Kumarajiva
The syllable SKA is a gateway because one enters that all the aggregation (skandha) of all dharmas cannot be attained.
入塞迦字門，悟一切法聚積蘊性不可得故
Xuanzang
The syllable SKA is a gateway because one understands that the aggregated (skandha) nature of all dharmas cannot be attained.
SKA because no skandhas are apprehended.
Conze
The syllable SKA means all mental phenomena are openings because of the nonrecognition of masses (skandha).
Jayarava