Seesaw and teeter totter are two names for the same piece of playground equipment. I grew up using the word teeter totter mostly, but was aware of seesaw, as it was used in books.
I was wondering whether it is a regional difference or a generational difference.
From thefreedictionary, I found that there are even more terms used for this equipment: tilt or a tilting board, teedle board, dandle or dandle board. Teeter or teeterboard, and teeter-totter, which is probably the most common term after seesaw. So it is indeed a regional term,
which also explains why Google Ngrams has no recorded use of teeter totter in British English:
Link to Ngram for seesaw teeter totter in British English
Yet, if seesaw was in use since before 1800, how and why did teeter totter come into use seemingly all of a sudden just before 1920?
Link to Ngram for seesaw teeter totter in American English
Best Answer
The answer to your question is that it is a regional not a generational difference.
Teeter-totter is the most widespread in America. Seesaw is specifically Southern. Dandle is from Rhode Island. Other regional variants include dandle board, teedle board, teeter, teeterboard, tilt, and tilting board. See the Dictionary of American Regional English for details.
Etymologically, the word teeter-totter was formed by reduplication of either titter or totter. It derives from titter, now a dialect form for teeter, and totter, which means the same thing. The OED also attests titter-totter, and says to see the Engl. Dial. Dict. for details. The earliest citation is:
See-saw is also a reduplicative word, and its earliest citations are also from the 1600s, although a bit later than the previous one. However, those are all just interjections. The first noun use is this one:
And the first verb citation is this: