node - any bulge or swelling of an anatomical structure or part

plant process, enation - a natural projection or outgrowth from a plant body or organ

mineralogy - the branch of geology that studies minerals: their structure and properties and the ways of distinguishing them

geode - (mineralogy) a hollow rock or nodule with the cavity usually lined with crystals

lump, hunk - a large piece of something without definite shape; "a hunk of bread"; "a lump of coal"