(1) Instead (adv)
: as a
substitute or
replacement :
�We
ordered tea
but were served coffee instead.�
(2) preferably (adv) : ideally;
by preference; if one had a choice; more readily or willingly; ideally; if possible; by choice; much sooner; in or for preference;
"clean it well, preferably with warm water"; �Take exercise, preferably in the fresh air�.
* Thus, �instead� is used when
there is a substitute; �They might instead choose to pay a visit
to the supermarket or the train station.� (No preference is available.)
* �Preferably� is used to express preference without
mentioning a substitute; �They might pay a visit to the supermarket preferably
in the morning�. (Preference is confined with the morning.)