Complement

1. That which is required to supply a deficiency, or to complete a symmetrical whole.
2. Something added for ornamentation; an accessory.
3. That which fills up or completes; the quantity or number required to fill a thing or make it complete.
4. The interval wanting to complete the octave; -- the fourth is the complement of the fifth, the sixth of the third.
5. A compliment.
6. Full quantity, number, or amount; a complete set; completeness.
7. To supply a lack; to supplement.
8. The whole working force of a vessel.
9. To compliment.
10. A second quantity added to a given quantity to make it equal to a third given quantity.