(botany) That part of a leaf and petiole that grows from a basal meristem.

plural of free speech zone

(politics, US) An area set aside in public places for the purpose of protesting.

(Buteo albonotatus), a medium-sized hawk of warm, dry parts of the Americas

plural of zone-tailed hawk

A concept developed by Soviet psychologist and social constructivist Lev Vygotsky: the difference between what a learner can do without help and what he or she can do with help.

(embryology) A region of mesenchymal connective tissue that carries instructions which direct the developing limb bud to form along the anterior-posterior axis.

plural of tow-away zone

plural of foveal avascular zone

(anatomy) The part of the retina, lacking blood vessels, that is the centre of the macula