Shaped like a sickle; falcate in form; falciform; drepaniform.
The Century Dictionary (Public Domain)
Use "sickle-shaped" in a sentence
"I think fish with lunate tail fins (meaning crescent or sickle-shaped) such as tuna, various jacks, and marlin can exert more proportionately more force than those with broad tails such as bass or trout."
"The November 1910 issue of the medical journal Archives of International Medicine (Arch Intern Med 1910: VI (5): 517-521) published a report by Dr. James B. Herrick titled, "Peculiar elongated and sickle-shaped red blood corpuscles in a case of severe anemia.""
"New marrow produces healthy red blood cells to replace the sickle-shaped ones that can't squeeze through small blood vessels, the cause of the disease's pain, infections and life-threatening organ damage."