(religion) Worship that is self-invented; superstitious observance without divine authority.

white willow

plural of tenant at will

One who holds lands at the will of the owner.

(biochemistry, medicine) A blood glycoprotein involved in platelet adhesion to wound sites during hemostasis.

plural of willow tree

The willow warbler (Phylloscopus trochilus).

plural of willow wren

(Scotland, archaic) Something that comes of its own accord; an illegitimate child.

rose campion (Silene coronaria, syn. Lychnis coronaria)