hyd - until, as long as
Conjunctions are linking words e.g. and , but , because , or. They are used to connect clauses or sentences to form more complex sentences. e.g. 'I want to go out tomorrow but it is going to rain all day.' The words after , before, after, when , as, while, until, since, are conjunctions. Since they indicate when things happen they are called time conjunctions or conjunctions of time .
Many Welsh conjunctions take a particular construction ( ' i' or ' bod' ) to link them with what follows in the sentence.
Hyd takes neither the 'i' or 'bod' constructions and is immediately followed by the verb when used as a conjunction.
see: How do conjunctions work in Welsh? for more details.