An illustrated STEM encyclopedia covering the top 100 words that kids need to know. Do you know all about A toms? Or what  B ioluminescence is? Discover these terms and more in this illustrated STEM encyclopedia. Organized in alphabetical order and each concept beautifully illustrated with humor and charm, these 100 essential words will fascinate scientifically minded young readers, from those ABCs all the way down to  X -rays, the terrifying  Y angchuanosaurus and even the true definition of  Z ero!  There is a contents list at the front and a full index at the back, plenty of extra words and definitions . . . plus mind-boggling facts, too. This is  the  book for STEM fans! Collated and written by bestselling STEM author, Jenny Jacoby, and illustrated by award-winning illustrator, Vicky Barker. STEM stands for "Science, Technology, Engineering, and Math." These core subjects are imperative in a child's education to help them understand the world and thrive in it!