IPO Allotment Process Working

Depending on the level of oversubscription, the allotment is done either on a proportionate basis or through a lottery. What I want to know is—when the allotment is done on a proportionate basis, it’s said that each applicant will receive at least one lot. Does this ‘one lot’ mean a single lot of shares, or the minimum lot size specified under that particular investor category?

Each one lot allotted means 1 lot in that particular category of HNI like 2 lakh and 10lakh or 1 lot which is of around 15,000 ?