Book designers and bookbinders will have the need to know these three terms, if only for clarity when dealing with some customers. It might be best not to use them ~ not everyone is familiar with them ~ maybe better to say 'on the left hand side of the open spread' ~ which is self explanatory.
Spread is probably self-explanatory, certainly when used in an appropriate context. It refers to any two adjacent pages when a book is opened.
Recto refers to the right-hand page of the spread ~ nudge...nudge...'R' for Recto...'R' for Right ~ I often need this reminder.
Verso is the page on the reverse of the recto. (...VERSo...reVERSe...) or it is the opposite page to the recto of a spread.