Sentence:  For the purposes of this clause, residing in Oxford shall mean the occupation of a dwelling-house or lodging in Oxford with <WSD>pernoctation</WSD>, and residing in College shall mean the occupation of rooms in College, or of a house in immediate communication with the College, with <WSD>pernoctation</WSD>. 
Meaning of the word marked with <WSD> tags:  An overnight stay; action (or instance) of abiding through the night at a location.