matrix ma·trix (mā'trĭks)
n. pl. ma·trix·es or ma·tri·ces (mā'trĭ-sēz', māt'rĭ-)
A surrounding substance within which something else originates, develops, or is contained.
The formative cells or tissue of a fingernail, toenail, or tooth.
See ground substance.
A specially shaped instrument, plastic material, or metal strip for holding and shaping the material used in filling a tooth cavity.