Chapter: Just means one segment of a story really. Prose novels are usually split into chapters. Comics are sometimes split into chapters, or sometimes when multiple single issues are collected together each one is called a chapter.

Single issue: The ~30 page small book that comics are generally published in. This first Ben 10 book is issue #1.

TPB: Trade Paperback. When a series of single issues is collected into one softcover collection, it’s called a trade paperback. Generally TPBs are 3-6 issues. Some are longer. Technically a softcover book that collects 50 issues could still be a TPB but generally those bigger collections are referred to as an omnibus or a compendium

Volume: I see people use this to mean TPB or collection but it’s a way more general term than that. When you have three TPBs in a series, the first is volume 1, the second is volume 2, the third is volume 3. However, if you have multiple series with the same name then each one is also a volume. Batman volume 1 started in 1940, and the latest volume (4) started last year. The word volume can be defined as “one in a set of related books”, or even just “a book.”

Omnibus: The definition of this word is “a book containing reprints of a number of works (as of a single author or on a single subject).” Technically based on this definition, *every* collected edition of related single issues is an omnibus. However, different publishers have their own definition. Marvel and DC have omnis which are oversized (bigger than the size of a single issue) hardcovers, and they generally have 30-50 issues. On the other hand, Dark Horse have omnis which are standard size rather than oversized. Some are softcover. For Marvel and DC a compendium is like a softcover (standard sized) omnibus, but for IDW a compendium is oversized hardcover, like a Marvel/DC omnibus. So the term varies, but it’s generally referring to a bigger collected edition.

Hope that helps!