supine

1. ADJ If you are supine, you are lying flat on your back. 仰卧的[正式]

...bedridden persons confined to the supine position. ...那些只能仰卧的久病不起的人。

2. ADV Supine is also an adverb. 仰卧地[ADV after v]

I lay supine on the poolside grass. 我仰面躺在游泳池边的草地上。