so long

so long

See you later; goodbye. So long, have a good weekend. I think we're ready to go. So long!
See also: long
Farlex Dictionary of Idioms.

so long

Good-bye. So long, see ya later. It's been good talking to you. So long.
See also: long
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

so long

Good-bye, as in So long, we'll see you next week. The allusion here is puzzling; long presumably means "a long time" and perhaps the sense is "until we meet again after a long time," but the usage has no such implication. [Colloquial; first half of 1800s]
See also: long
The American Heritage® Dictionary of Idioms by Christine Ammer.

so ˈlong (for now)

(informal) goodbye until we next meet: So long for now. I’ll see you soon.
See also: long
Farlex Partner Idioms Dictionary

So long

interj. Good-bye. It’s been good talking to you. So long.
See also: long
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

so long

Good-bye. This colloquial usage has been around since the first half of the 1800s and its origin is puzzling. “Long” may be short for “a long time,” but there is no such implication in the phrase. The American radio newscaster Lowell Thomas, active from 1930 to the mid-1970s, had a standard sign-off, “So long . . . until tomorrow.” Today the phrase is heard less often than a newer form of good-bye with an equally puzzling allusion, take care.
See also: long
The Dictionary of Clichés by Christine Ammer
See also:
  • will go a long way
  • all day long
  • for (so) long
  • for long
  • long since
  • go around Robin Hood's barn
  • enjoy a long run
  • take the long view
  • long gone
  • over the long term
References in periodicals archive
Nicholson hinted in the report at the "continuum of care" so often spoken of today, stating that the immediate needs of older people seeking long-term care would be replaced by the need for "slowly but steadily increasing amounts of care." Because people generally require more care gradually, she urged that "the facilities providing the service be so organized and administered that there need be no sharp break in the provision of care for the individual," adding that "it should not be necessary to admit an elderly person to one home where he can remain only so long as he needs some care but not very much, and then to discharge him from that home and admit him to another when his needs increase.
"A good look back over our shoulders"
Moreover, so long as an inflationary environment persists, these costs are ongoing and cumulative.
Statements to Congress
Also, premiums paid for a qualified longterm care insurance policy can be deducted from taxes as a medical expense, so long as medical expenses exceed 7.5% of adjusted gross income.
LTC insurance: clarifying the tax clarifications