horizontal       
 adjective uk/ˌhɒr.ɪˈzɒn.təl/ us/ˌhɔːr.ɪˈzɑːn.t̬əl/
C1 水平的;与地面(或底边、顶边)平行的;横的
parallel to the ground or to the bottom or top edge of something
  Draw a horizontal line across the bottom of the page. 在本页底部画一条水平线。 
 Keep the patient horizontal with the feet slightly raised. 让病人平躺,双脚略微抬高。 
 Compare: vertical adjective
 - More examples
 - On this graph, time is on the horizontal X-axis, and distance is on the vertical Y-axis.
 - Try to avoid wearing clothes with horizontal stripes as they're really not flattering.
 
horizontal       
noun [ C usually singular ] uk/ˌhɒr.ɪˈzɒn.təl/ us/ˌhɔːr.ɪˈzɑːn.t̬əl/
 水平线;水平面;水平位置
a horizontal line, surface, or position
  Rotate it slowly from the horizontal into a vertical position. 慢慢将它从水平位置旋转到垂直位置。