Royal Institute Dictionary

The Royal Institute Dictionary (RID; Thai: พจนานุกรม ฉบับราชบัณฑิตยสถาน, RTGS: Photchananukrom Chabap Ratchabandittayasathan, pronounced [pʰót.tɕā.nāː.nú(ʔ).krōm tɕʰā.bàp râːt.tɕʰā.bān.dìt.tā.já(ʔ).sā.tʰǎːn]) is the official and prescriptive dictionary of Thai language, published by the Royal Society of Thailand.

The Royal Society of Thailand has published four fully revised editions of the dictionary, and many intermittent reprintings with minor revisions. Each of the major revisions is associated with a significant year in Thai history, although in the case of the 1999 and 2011 editions, the actual publication date is a later year.