August 7, 2014
Weekly Language Usage Tips: back on or back by
Tip: Back on or back by
A reader writes:
I would like to ask, if you say, for example, “I’ll be back by Monday” versus “I’ll be back on Monday.” Do both sentences mean that you will be back home on that Monday and not before?
I can answer this. Both sentences mean that the speaker will be back on Monday, but the moment of return may differ. “I’ll be back by Monday” means that the speaker will have returned by Monday definitely, but he/she will be there Monday at the latest—the arrival might very well happen earlier.
“I’ll be back on Monday” can be interpreted in a couple of ways. I think that the most common read on this is that the speaker will return on Monday—that is the day of arrival. While I believe that this (arrival ON Monday) is the most common interpretation, the sentence could also be read in a different way: the speaker will be there on Monday, but the moment of arrival is not specified, and it could occur at any time prior to Monday.
I’ll be back on Monday, but I’ll also be back on Sunday.
Not the most common reading of this, but it is possible. If the speaker wants to specifically designate that Monday is the day of return, he she should leave out the preposition completely and simply state, “I’ll be back Monday.” That eliminates the ambiguity completely.