The most common and most likely answer to this crossword clue is the 9 letter word SUBSPACES
S
U
B
S
P
A
C
E
S
Buddy explains!
The straight part
We know that "Contained lots of elements" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case contained lots of elements = subspaces.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SUBSPACES mean?
SUBSPACES noun- A subset of a space which is a space in its own right.
- Any (often unspecified) method of communicating faster than light speed.