the only one
- uniqueOnly one exists
- soleFoot's bottom surface
- singularOne in number
- solitaryExisting alone, apart
- loneExisting by itself
only · exclusive · irreplaceable · one-of-a-kind · matchless · unrivaled · peerless · chosen · special · rare · precious · single · standalone · isolated · beloved · soulmate · exception · distinct
quantity/plurality
the only onemany
A large quantity
numerous · multiple · several · countless · innumerable
uniqueness/commonness
the only onea dime a dozen
Abundant and unremarkable
ordinary · common · typical · run-of-the-mill · commonplace
replaceability
the only oneinterchangeable
Able to replace another
replaceable · expendable · disposable · substitutable · fungible