Get on (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">get on</span>' is the definition.<br/ ><span class="explanation-format__explanation">(eg boarding a train)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for board that I've seen before include "Get on - governing body" , "Food - table - directors" , "See 13 across" , "Strip of timber" , "Collection of directors" .)
(Other definitions for mount that I've seen before include "Fix onto a backing" , "Climb - Everest, for example" , "Get on - horse" , "seat" , "The height" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">get on</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for age that I've seen before include "Length of life" , "Years since birth" , "Time in years" , "Period of time" , "Grow older" .)