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
Berislav	-	Croatian, Medieval Slavic
Quentin	['kwentin]
Ephraim	EE-free-im (English), EE-frəm (English), E-free-im (English), E-frəm (English)	Biblical, Jewish, Biblical Latin, Biblical Greek
LiÊN	-	Vietnamese
Sissy	SIS-ee	English
BjØRg	-	Norwegian