adj

• (chiefly biology) Larger at the tip than at the base; club-shaped.
  "Claviform is the reverse of stalactitic; it is composed of club-shaped parallel rods which adhere by their thin extremities. Examples, brown and black hæmatite."

noun

• (palaeography) An image or symbol which is club-shaped, that is, larger at the tip than at the base.
  "The claviform comprises a vertical line with a bulge at one side; but unlike the buttocks on the stylized females, the bulge is usually on the middle or the upper half of the 'sign'! It has been suggested that the 'upper bulge' on a claviform instead represents breasts, but this is based on supposedly stylized statuettes from Dolni Vestonice and elsewhere, comprising a rod with two little lumps near the top, and thus on analogies with sites even further away in space and time from the claviforms."

adj

• (chiefly biology) Shaped like a nail (“a metallic spike-shaped fastener”).
  "CLAVOPORA Busk, 1874. Colony small, erect, coriaceous, claviform (nail-shaped), with two well differentiated parts: [...]"