/ ˌhɒrɪˈzɒntl; NAmE ˌhɔːrəˈzɑːntl; ˌhɑːr-/ adjective , noun
■ adjective
flat and level; going across and parallel to the ground rather than going up and down :
horizontal lines
( informal )
—compare vertical
► hori·zon·tal·ly / -təli; NAmE / adverb :
Cut the cake in half horizontally and spread jam on one half.
■ noun
1.
the hori·zon·tal [ U ] a horizontal position :
He shifted his position from the horizontal.
2.
[ C ] a horizontal line or surface
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WORD ORIGIN
mid 16th cent. (originally meaning something of or at the horizon): from French , or from modern Latin horizontalis , from late Latin horizon , horizont- , from Greek horizōn (kuklos) limiting (circle).