Dictionary.com Thesaurus.com

angle of elevation vs. angle of depression

angle of elevation

[ang-guhl uhv el-uh-vey-shuhn] / ˈæŋ gəl əv ˌɛl əˈveɪ ʃən /

noun

Surveying.

the angle between the line from an observer or instrument to an object above the observer or instrument and a horizontal line.

angle of depression

Surveying.

the angle between the line from an observer or instrument to an object below either of them and a horizontal line.