C. solida may refer to:
Archips solidus, a species of moth, synonymized as Cacoecia solida Meyrick, 1908 Cellana solida, a species of sea snail Clathrodrillia solida, the solid drillia, a species of sea snail Clavaria fragilis, fairy fingers, a fungus synonymized as Clavaria solida Gray, 1821 Coelolepis solida, an extinct species of jawless fish Corydalis solida, the fumewort, a flowering plant of northern Eurasia Crepidula adunca, a species of sea snail, synonymized as Crepidula solida Hinds, 1845 Eucithara solida, a species of sea snail, synonymized as Cytharopsis solida (Reeve, 1846)