BTO noun 1verb 1adjective 2forms 3 noun1 •(Singapore) A build-to-order flat. verb1 •(Singapore) To make an application for a build-to-order flat. adjective2 •Initialism of built to order. •(Singapore) Initialism of build-to-order.In 2013, over a decade after the BTO flat system was introduced, singles were finally allowed to buy subsidised flats directly from the HDB, but only two-room flats. — 2016 formsBTOed · BTOing · BTOs