In 'she realised that the pot was ready', the underlined subordinate part is a:

1. The clause beginning with that answers what she realised. 2. It does the work of the object of the verb realised. 3. A subordinate clause doing that job is a noun clause. 4. So the answer is a noun clause. _Source: syllabus English Poorvi, Unit 2 'The Pot Maker'_