Kalmar "ectomorphy" tana nufin nau'in jiki ko yanayin jiki wanda yake da ƙwanƙwasa, siriri mai ginawa, tare da ƙarancin kitsen jiki da yawan tsoka. Yana daya daga cikin manyan nau'ikan jiki guda uku da aka gano a cikin ka'idar somatotype na William H. Sheldon, tare da endomorphy (zagaye da laushi) da kuma mesomorphy (muscularity and athleticism). Mutanen da ke nuna halayen ectomorphic suna da kunkuntar firam, dogon gaɓoɓi, da saurin metabolism. Ana amfani da kalmar "ectomorph" sau da yawa don kwatanta mutane masu wannan nau'in jiki.