In another question, I asked if Ajamila attained Moksha and the reply was "He attained the abode of Vishnu". Is that only a Vaishnavite definition of Moksha? What other definitions exist in scripture?
Yes, it differ from sect to sect. In Kashmiri Shaivism which is non dual Shaivism, enlightenment is not to attain any physical place but it is self realization. From ParamArthsAra of AchArya Abhinavgupta -
मोक्षस्य नैव किञ्चिद्धामास्ति न चापि गमनमन्यत्र।
अज्ञानग्रन्थिभिदा स्वशक्त्यभिव्यक्तता मोक्षः॥६०॥
In the case of Liberation (mokṣasya), there is neither (na eva kiñcid asti) an abode (dhāma) nor (na ca api) a going (gamanam) to another place (anyatra). Liberation (mokṣaḥ) (is simply) the manifestation (abhivyaktatā) of one's own (sva) Powers (śakti) by the piercing (bhidā) of the knot (granthi) of ignorance (ajñāna)||60||