there
The spelling there is used for two words with completely different pronunciations and uses.
Adverb of place
There (pronounced /ðeə(r)/) is an adverb meaning ‘in that place’.
- What’s that green thing over there?
- ***There’*s the book I was looking for.
note
For the difference between here and there, (see here).
Introductory subject
There (most often pronounced /ðə(r)/) is used as an introductory subject in sentences beginning there is, there are, there might be, etc. For details, (see here).
- ***There’*s a book under the piano.