What does the squiggle mean
I came across the following while looking up a word in Teanglann.
‘Nach bhfuil leat ~ an leabhar seo? Have you brought nothing but this book?’
And I was wondering what the ~ meant
It's the word that the entry is about. They're saving space by not repeating it in full. At a guess this is a holdover from print dictionaries, where space is at a premium.
Quite right. Consider the entry for grianghrafadóireacht,
grianghrafadóireacht, f. (gs. ⁓a). Photography.
— “⁓a” is much less verbose than “grianghrafadóireachta”.
In Hart-Kevin’s example from the “Phrases” section of the nach entry,
ach » Nach bhfuil leat ⁓ an leabhar seo? Have you brought nothing but this book?
the swung dash represents ach rather than nach, and “ach »” there is a link to the ach entry.
Ye I'd agree with the comments. I looked up about this after seeing your question. It's called a tilde and represents an undefined word. In this dictionary it represents the keyword 'ach' (but). ‘Nach bhfuil leat ~ (ach) an leabhar seo? Have you brought nothing but this book?’ I suppose it makes the position stand out to make it's position easier to find. Two keywords above the symbol ~ represents the keyword 'abair' and the symbol meaning changes for each keyword. Hope that helps.