• accessory, assistant, aux, auxiliary, collateral, ersatz, expletive, mock, spare, supplementary
• to compensate, to complement, to make good, to make up, to recover, to refill, to reinstate, to supersede, to supplant, to supplement, to supply
• supplementary estimates
• spare, spare tyre, spare wheel
• supplementary estimates
• to complement, to eke out, to make up, to recoup, to recover
• prosthesis, prosthetic dentistry