In German an »Umschlag« is male, and a »Kuvert« is neuter.
I thought an English »envelope« would be neuter, too.
Turns out, those things are male or female.
»Male envelopes have red parameters and females blue.« 🤦🏼

#Wikipedia #LLoydGeorge #LloydGeorgEnvelope #NHS
https://en.wikipedia.org/wiki/Lloyd_George_envelope