Answer: guaiacs

AnswerCrossword Clue
guaiacsthe hard, heavy wood of such a tree; guaiac
guaiacsGUAIAC, a medicinal resin, also GUAIACUM, GUAIOCUM
guaiacsgreenish-brown resin obtained from the guaiacum tree, esp. from Guaiacum officinale, used in varnishes, as a food preservative, and in medicine in various tests for the presence of blood