Dictionaries have been removed from classrooms in southern California schools after a parent complained about a child reading the definition for "oral sex".

Merriam Webster's 10th edition, which has been used for the past few years in fourth and fifth grade classrooms (for children aged nine to 10) in Menifee Union school district, has been pulled from shelves over fears that the "sexually graphic" entry is "just not age appropriate", according to the area's local paper.

The dictionary's online definition of the term is "oral stimulation of the genitals". "It's hard to sit and read the dictionary, but we'll be looking to find other things of a graphic nature," district spokeswoman Betti Cadmus told the paper.

While some parents have praised the move – "[it's] a prestigious dictionary that's used in the Riverside County spelling bee, but I also imagine there are words in there of concern," said Randy Freeman – others have raised concerns. "It is not such a bad thing for a kid to have the wherewithal to go and look up a word he may have even heard on the playground," father Jason Rogers told local press. "You have to draw the line somewhere. What are they going to do next, pull encyclopaedias because they list parts of the human anatomy like the penis and vagina?"

A panel is now reviewing whether the Menifee ban will be made permanent. The Merriam Webster dictionary joins an illustrious set of books that have been banned or challenged in the US, including Nobel prize winner Toni Morrison's Song of Solomon, which last year was suspended from and then reinstated to the curriculum at a Michigan school after complaints from parents about its coverage of graphic sex and violence, and titles by Khaled Hosseini and Philip Pullman, included in the American Library Association's list of books that inspired most complaints last year.