शिखर —      शिखा —

शिखर  m) peak (pico, máximo), top, summit (cumbre, apogeo, cúspide), pinnacle; vortex, apex

शिखा  f) distinctive lock of hair [rizo, mechón] on the crown of the head (traditionally worn by the Hindus), topknot (moño, cresta); apex (ápice, punta)