eBay does not use and, or, or not, which are treated as ordinary search words.
To match two or more words, just type the words separated by spaces.
Example: concertina germany
To match an exact phrase (contiguous), use quotes around the phrase.
Example: "maccann duet concertina"
To match any one of two or more words anywhere, put the words in parentheses separated by commas (no spaces).
Example: (wheatstone,lachenal,jeffries) (matches any one or more)
If you prepend a word with - that word is required not to be present.
Example: concertina -tori -amos
If a query word ends with a * all words which begin the same way will match.
Example: concertin* (matches concertina, concertinas, concertinist, etc.)
Example: 186* (matches 1860, 1860s, 1860-1880, 1861, etc.)
All of these techniques can be combined.
Example: concertin* (wheatstone,lachenal) 18* -torn -cracked -loose