Victorian One-Piece Undergarment

I am not really sure what to call this piece. It is handmade and measures about 11" across shoulders X 26" from shoulder to hem X 17.5" across bodice. It is too large for a baby more of a toddler size. It is hard to give accurate measurements since there is no defined shoulder. There are some spots as shown and the opening appears to have the original button.

Please be advised as with any vintage/used clothing, shoes or fabrics there may be small tears, spots, fading, pilling, wear or pulled threads.  Most are repairable and stains are treatable. I try to point out the flaws so read carefully and look at photos closely. Thank you for looking and message if you have questions!