What does Philately mean? [a conversation story]

A: Today you can meet my brother, Jeff.
B: Okay, cool. Tell me about him.
A: He's really into philately.
B: What's philately?
A: Stamp collecting.
B: Stamp collecting. Okay...uh, how do you spell philately?
A: P-H-I-L-A-T-E-L-Y
B: Philately does not sound like it could mean stamp collecting.
A: Why not?
B: Generally, if a word has "ly" at the end of it (i.e., the letters 'L' 'Y'), which Philately sounds like it does, then it is an adverb, something that modifies a verb, but stamp collecting should be a noun. How can Philately mean stamp-collecting?
A: Ummm
B: Okay, let's think about this. Really, stamp collecting is the present participle (or is it gerund) of "collect stamps," which is a verb phrase, so we can get a little closer to an adverb there, but really, adverb and participle seem to be opposite directions, grammatically--at least to me. What do you think.
A: I'm not really following what you're saying. Why is this such a big deal to you?
B: It was the first think you said about your brother, so it seems to be important to your family at least. When I learn a new word, I want to know where it came from.
A: Okay, fair enough, but I'm still a bit lost on the grammatical direction issue.
B: Let's try a different tack. What language do you think philately comes from?
A: Um, Greek probably.
B: Right, a P-H together usually means that, so...philately is probably a greek word.
A: What if L-Y means something different in Greek?
B: If it did, there probably would be some other words ending in L-Y that are nouns, but I can't think of any. Of course, there could be, but I think we would probably know that. In fact, I think the L-Y suffix might be Greek. What do you think?
A: No idea. Maybe we should just look it up.
B: Wait, before you do that. What about the "phil" connection?
A: Like stamp collecting is loving being late.
B: Um, yeah, something like that. What does "ate" mean in Greek?
A: Stamps! of course.
B: Really?
A: Well, that was just a guess. I mean, if philately means stamp collecting, then there has to be a stamp meaning in there somewhere, right?
B: Yeah, I guess you better look it up now.
A: Okay, here's what Google says: "The collection and study of postage stamps."
B: Okay, we already knew that. What about the origin.
A: Wait, I've got an idea. What if it's just a 'Y' at the end, not at L-Y.
B: Um, like...Philately is a form of Philatel or Philateling.
A: Exactly. Look, someone who does philately is a philatelist.
B: Okay, perhaps. So that would mean that the Greek word for stamp is probably either 'atel' or 'latel', right? Or maybe even 'ately'.
A: Good call. Okay, here's what dictionary.com says about the origin: It's from the French word philatélie, which comes from the Greek words phil- and atéleia. (Hopefully I pronounced those right.) Atéleia means "freedom from charges (taken to mean recipient's freedom from delivery charges by virtue of the stamp which sender affixed to the letter), literally, want of taxation," equivalent to a- a... + tél ... tax + -eia -y3"
B: Here, let me look at that.
*Pause while B reads the description. Let B also press a couple of links.*
B: I see. So you were right about the 'Y' being separate from the 'L'. Basically, this means that "ately" was originally "a-TEL-y" or something like that. The "a" is "not", the "tel" is "tax", and the "y" is making the "tel" into a noun, like inquiry. Cool, now I know all about Philately.
A: Um, no. You really don't. You know about the word, but you probably don't know much about the actual activity.
B: Good point. I'm sure your brother will be happy to tell me about that.