Technically true. But what matters is not the name put on something, but its real effects:

While not technical defaults, what do you make of:
1933: Executive Order 6102 and the1934 devaluation of dollar
1965: Elimination of silver from many coins
1970: All silver removed from coins
1971: De-pegged dollar from gold (triggered the oil price shock)
2008 onwards: Financial repression via regulation and QE