Example: Imagine a family moving into another house. They may try to take as much their belongings as they can during the move. Thus, one could say that they took "everything but the kitchen sink" with them, meaning they took nearly everything.
The origin of this phrase is not clear. Some believe it may have originated from World War II, however, that doesn't seem to be the case because there are recordings of the expression that come before. For instance, the earliest I could find this phrase in printed form is in a newspaper called The Syracuse Herald, 1918, where it reads:
"I have I shall rather enjoy the experience, though the stitlons are full of people trying to get out
and the streets blocked with perambulators, bird cages and 'everything but the kitchen sink.' "
The fact that the idiom has quotations around it would imply that it was already a known phrase at that time. Interestingly, there's another phrase that's very similar to this one. It goes "everything but the stove" or "everything but the kitchen stove." An example of this variant form is seen in the Jeffersonville National Democraft, 1894:
"I sold the chicken and got a dollar for them. John I got everything but the stove."
The form of the phrase that uses "kitchen sink," the earliest I could find it in writing is 1918. However, I can find the "stove" variant a bit earlier, as shown above. Hence, the "stove" variant appears to be older, and it may be that the "kitchen sink" form derived from this older, similar expression.
Note: This is not the case for every phrase, but there will certainly be times where the origin of a phrase is not clear. In such cases, what you'll usually see are theories or guesses that take a gander as to where the phrase may have come from, but these may not be accurate.
Additionally, the quotes that you will see on these pages are typically the oldest that I could find. These come from old books, poems, or newspapers, etc. Keep in mind, though, that there could be an older recording that I may have overlooked.
* After losing my job, my family had to move into a smaller and less expensive home. We took everything but the kitchen sink from our old spot when we moved into our new place.