[DNSB]

One recent purchase was 4 "novels" and 6 "novellas" in a series that were collected into an omnibus edition. Total word count for the omnibus was 184,392 (minus advertising, copyright notices, etc.). I then counted the individual items. The 4 "novels" came in at 32,451, 33,009, 34,822 and 39,230 words for a total of 139,512 words, the remaining 44,800 words would be the 6 "novellas". A quick word count of those showed 1 at 15,091 words which sneaks into novella territory. The remaining 29,789 words were spread fairly even across the remaining 5 "novellas" with only one coming close to 7,000 words.

So what I would say is that, being generous, I purchased 6 novellas and 5 short stories in an omnibus edition.

I was using the following word count definitions and yes, there is overlap:
Short story: usually over 1,000 words to 10,000 words
Novelette: 7,500 to 19,000 words
Novella: 10,000 to 40,000 words
Novel: over 40,000 words