You spelled it correctly in your question.
The correct spelling is "lying down."
aisle
The genetic developmental defect is spelled "Down Syndrome" or sometimes "Down's Syndrome."
The correct spelling is "decelerate" (slow down).
Cameron Poole.
The correct spelling is "lying down."
descendre
Bottom.
Lying down.
drop down list. i guess
The land down under is spelled "Australia."
The spelling is upside down, which is hyphenated upside-down when used as an adjective.
aisle
As in knelt down - the same way you did
The word "down" in French is spelled as "bas."
"Lying down" in French is spelled as "allongé".
The present tense spelling for "lie down" is "lie down."