| HEORTOLOGIST | • heortologist n. A person who studies heortology. • HEORTOLOGIST n. one who practises heortology, the study of religious feasts. |
| HOMOEOSTATIC | • homoeostatic adj. Alternative spelling of homeostatic. • HOMOEOSTATIC adj. relating to homoeostasis. |
| OCTOSTICHOUS | • octostichous adj. (Botany) octastichous. • OCTOSTICHOUS adj. in eight rows, also OCTASTICHOUS. |
| OPISTHOTONIC | • opisthotonic adj. Relating to opisthotonus. • OPISTHOTONIC adj. of or like opisthotonos, extreme arching backwards of the spine and neck as a result of spasm of the muscles in that region. |
| OPISTHOTONOS | • opisthotonos n. (Medicine) Sustained tetanic spasm in which the body is bent backwards and stiffened, as produced by various diseases. • OPISTHOTONOS n. extreme arching backwards of the spine and neck as a result of spasm of the muscles in that region, etc. |
| ORTHODONTIAS | • ORTHODONTIA n. the rectification of crookedness in the teeth, also ORTHODONTICS. |
| ORTHODONTICS | • orthodontics n. (Medicine) A specialty of dentistry concerned with correcting misalignment of teeth. • ORTHODONTICS n. the rectification of crookedness in the teeth, also ORTHODONTIA. |
| ORTHODONTIST | • orthodontist n. An orthodontic dentist. • ORTHODONTIST n. one who practises orthodontics. |
| ORTHOTONESIS | • orthotonesis n. The accentuation of a proclitic or enclitic. • ORTHOTONESIS n. accentuation of a proclitic or enclitic, as opposed to enclisis. |
| ORTHOTROPIES | • ORTHOTROPY n. the state of being orthotropic, growing along a vertical axis. |
| ORTHOTROPISM | • orthotropism n. The property of being orthotropic or orthotropous. • ORTHOTROPISM n. vertical growth. |
| PHOTOTROPIES | • PHOTOTROPY n. change of colour due to wavelength of incident light. |
| PHOTOTROPISM | • phototropism n. (Biology) The movement of a plant towards or away from light. • PHOTOTROPISM n. movement directed by light. |
| PROTOHISTORY | • protohistory n. The period between prehistory and history, during which a culture or civilization has not yet developed… • PROTOHISTORY n. the study of human beings in the times that immediately antedate recorded history. |
| TRAITORHOODS | • TRAITORHOOD n. the state of being a traitor. |
| TRICHOTOMOUS | • trichotomous adj. Divided into three parts, or into threes; forking three ways. • trichotomous adj. (Set theory) Such that, for all x and y in X, and for a binary relation R, exactly one of xRy, yRx or x=y holds. • TRICHOTOMOUS adj. divided into three parts. |
| TROPHOZOITES | • trophozoites n. Plural of trophozoite. • TROPHOZOITE n. in Protozoa, the trophic phase of an adult. |
| WITHOUTDOORS | • withoutdoors adv. (Archaic) outdoors. • WITHOUTDOORS adv. outdoors. |