Glossary
Sustained
The judge's ruling that an objection is correct: the lawyer can't ask that question, the evidence isn't admitted, or whatever the objection was about doesn't happen.
When you hear a judge say "sustained," it means the objecting party won that particular evidentiary fight. The witness doesn't answer the objected-to question. If a question already produced an answer, the judge will often instruct the jury to disregard it.
Whether jurors actually disregard things they've already heard is famously hard to control: that's why some objections come too late to fully fix the damage.