Sentence:  Some teachers festoon every spare inch of wall with vocabulary choices or maths techniques to use, which look great at first, but to some children might appear quite daunting. You'll probably see unfamiliar acronyms such as Walt (We Are Learning To). Be sure to ask what they <WSD>stand for</WSD> and how they are used in practice. 
Meaning of the word marked with <WSD> tags:  To mean; to symbolize; to represent