Another way to ponder
Let's not forget the other big ways in which JKR plays with words: portmanteau and word threads.
Portmanteaux are words coined by combining other words, like brunch comes from combining breakfast and lunch. JKR makes it a bit harder for us, though, since she follows the old practice of changing/adding/subtracting a letter here and there. Many of her portmanteaux are also of foreign origin, especially French, which she used to teach. Examples of this are Voldemort, basically meaning "flight of/from death", and Gringott's, translated as "miser of gold".
Word threads are everyday words that take on new or simply important meanings when they appear again and again, either identically or as homonyms. Examples are the constant reminders about things like trainers (sneakers) and socks... glass, glasses, windows, and mirrors...eyes, hands, arms and other body parts...colors/shades/tints like red/Rubeus, white/Albus/pale/paperwhite, and Black/Nigellus/dark/grey/greying. Other threads to look for include any mention of a type of tree or bird. I could go on forever listing threads here, but I wish to discuss them in depth as we come across them.
I do hope my next post is chapter-specific. :)