It's opposite D in the circle of fifths

• Note that's equivalent to G-sharp: Hyph
• Neighbor of G, on a piano
• G-sharp, alternatively
• Not quite an A
• Major key
• Fix __ (do tire repair)
• Middle of three black keys
• Most common key of Chopin's piano pieces
• Key favored by Chopin

Wiktionary Word definitions in Wiktionary
adv. (context obsolete English) level with the ground; flat.