have a fix on (something)

To have a firm, clear understanding or determination of something. I hope everyone has a fix on the material, as you'll be tested on it next week. I thought I had a pretty good fix on English idioms, but I don't understand this one at all!

Common Names:

Name	Pronounced	Usage
Ioubal	-	Biblical Greek
Sveva	-	Italian
Pooja	-	Indian, Hindi, Marathi, Gujarati, Bengali, Punjabi, Telugu, Malayalam, Tamil, Kannada, Nepali
Lavonne	-	English
Andres	-	Estonian
Llewelyn	-	Welsh