A mixture of gums, resins, spices and fixatives that make a perfumed vapor when burned. Long associated with worship because of the fire and rising smoke involved, it also perfumed the stench of sacrificial alters.
In Hebrew, "Keturah" is "incense" as in "the sons of Keturah" (tribes with incense caravans) and other associations.
Today, incense (depending on recipe) is burned as a protective device and to assist in manifesting one's desires as well as for worship and pleasure.
Beware: only the best incense sticks use resins as fixatives. Many of us have burnt incense "fixed" with animal dung.
See also: Frankincense.