octagon /okˈtə-gon/ noun

(Gr gōniā an angle) a plane figure of eight sides and eight angles (also adjective)

octagonal /-taˈgən-əl/ adjective

octaˈgonally adverb

octahēˈdral adjective

octahēˈdrite noun (mineralogy)

Anatase, crystallizing in square bipyramids

octahedron /ok-tə-hēˈdrən/ noun (pl octahēˈdrons or octahēˈdra)

(Gr hedrā a base) a solid bounded by eight plane faces

octamerous /ok-tamˈ/ adjective

(Gr meros a part) having parts in eights

octameter /ok-taˈmi-tər/ noun (Gr metron a measure; prosody)

A line of eight feet or measures

Octanˈdria plural noun

(Gr anēr, andros a man) a Linnaean class of plants with eight stamens

octanˈdrian adjective

octandrous /ok-tanˈdrəs/ adjective (botany)

Having eight stamens

octangular /ok-tangˈgū-lər/ adjective

Having eight angles

octapodic /ok-tə-podˈik/ adjective

octapody /ok-taˈpə-di/ noun (Gr pous, podos foot; prosody)

A line of eight feet

octastich /okˈtə-stik/ noun (Gr stichos row, line; prosody)

A strophe of eight lines, also octastichon /ok-taˈsti-kon/

octaˈstichous adjective (botany)

In eight rows

octastrophˈic adjective (Gr strophē strophe; prosody)

Consisting of eight strophes

octastyle, also octostyle /okˈtə-stīl/ adjective (Gr stȳlos a column; architecture)

Having eight columns at the end

A building or portico so designed

octavāˈlent adjective (chem)

Having a valency of eight