From an unused root meaning to smell sweet; an aroma -- sweet (spice).
H5561. sam
[סַם]16 noun masculine spice, used in incense; — only plural absolute סַמִּים, and only P, Chronicles; Exodus 30:34 (twice in verse), elsewhere קְטֹרֶת (הַ)סַּמִּים incense of spices 25:6 8t. Exodus; Leviticus 4:7; 16:12; Numbers 4:16; 2 Chronicles 2:3; 3:11.