fragrant spice: an aromatic ingredient used to make the holy incense
This word is always plural in the Bible, and it always points to the same thing: the sweet-smelling ingredients that were ground and blended into the sacred incense burned before God. These are perfuming aromatics, gums and resins prized for their scent, not seasonings meant to flavor food.
Almost every time the word appears it sits inside one fixed phrase, "the incense of spices," the standard name for the fragrant incense offered on the golden altar in the tabernacle and temple. Only once does the word step out of that phrase to name the raw materials directly: in Exodus 30:34 God tells Moses to take fragrant spices, then lists them one by one (stacte, onycha, and galbanum) alongside pure frankincense (לְבֹנָה).
So this word names the aromatic components, while the finished, burnable compound they produce is the incense itself (קְטֹרֶת). A closely related word covers the fragrant spices blended instead into the holy anointing oil (בֹּשֶׂם); the two often stand side by side in the same lists of sanctuary materials.