1. Support, pedestal, stand, bottom, foundation, substructure, ground, bed: "The lamp stands on a circular base."

"The tall building utilizes several kinds of bases or foundations to hold it solidly in place."

2. Foundation, essence, principle, root, core, heart, key, rudiment, ground, source: "The base of his argument is that our price is too high."
3. Essential ingredient, principal constituent: "The soup has a tomato base."
4. Camp, station, post, billet, installation, garrison: "The weary troops marched back to their base."

"U.S. military units still have several bases in Europe."

5. To derive from, to model on, to found on: "This song is based on an old folk tune."
6. Station, garrison, locate, situate, install, ground, establish, place: "The company’s headquarters is based in Berlin. The army’s 3rd Armored Division was based at Fort Knox."
7. Inferior, poor quality; alloyed, debased, adulterated, impure, spurious: "Zinc and brass are base metals."
8. Mean, vile, low, contemptible, despicable, ignoble, shameful, immoral, sneaky, petty: "Cheating at cards is a base practice."