A large-sized note is a bill of any denomination of U.S. currency printed between 1863 and 1929. This is in contrast with small-sized notes, which were printed starting in 1928.
"Size" in this context referring to physical dimension rather than denomination. According to the BEP, the small-sized notes measure 2.61 by 6.14 inches (66 by 156 mm) with a thickness of 0.0043 inches (110 µm). Large-sized notes were 3.125 by 7.4218 inches (79.38 by 188.51 mm).
Large-sized notes exist in denominations of $1 through $10,000. The most common large-sized notes are the Federal Reserve Notes of Series 1914 and 1918. These are detailed below, but are only a subset of all large-sized notes made by the Bureau of Engraving and Printing (BEP).