put on one's thinking cap

Think or reflect seriously, as in A new slogan? I'll have to put on my thinking cap for that. This term originated in the late 1800s and replaced considering cap, which dates from the early 1600s.

Common Names:

Name	Pronounced	Usage
Terentius	-	Ancient Roman
Arrhenius	[a:r'reiniʊs]
Khaled	-	Arabic
Antoinette	awn-twaw-NET	French
Luitgard	-	German, Ancient Germanic
Jacqueline	zha-kə-LEEN (French), zhak-LEEN (French), JAK-ə-leen (English), JAK-ə-lin (English)	French, English