thou /ðaʊ/verb 2/θaʊ/ noun 2forms 4 verb2 •To address (a person) using the pronoun thou, especially as an expression of contempt or familiarity.Don’t thou them as thous thee! – a Yorkshire English admonition to overly familiar children •To use the word thou. thou /θaʊ/ noun2 •(slang) A thousand, especially a thousand of some currency (dollars, pounds sterling, etc.).Whoa there, big spender — that'll cost you a few thou. Are you sure you can afford it? •A unit of length equal to one thousandth of an inch (25.4 µm).We just wanted to take off a few thou, which we easily did with fine sandpaper. formsthoued · thouing · thous · thouest