to believe especially on uncertain or tentative grounds; "Scientists supposed that large dinosaurs lived in swamps"
talk over conjecturally, or review in an idle or casual way and with an element of doubt or without sufficient reason to reach a conclusion; "We were speculating whether the President had to resign after the scandal"
invest at a risk; "I bought this house not because I want to live in it but to sell it later at a good price, so I am speculating"
air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time
breathing device consisting of a bent tube fitting into a swimmer's mouth and extending above the surface; allows swimmer to breathe while face down in the water