US Code
CHAPTER 1— RULES OF CONSTRUCTION
§ 1. Words denoting number, gender, and so forth

In determining the meaning of any Act of Congress, unless the context indicates otherwise— words importing the singular include and apply to several persons, parties, or things; words importing the plural include the singular; words importing the masculine gender include the feminine as well; words used in the present tense include the future as well as the present; the words “insane” and “insane person” shall include every idiot, insane person, and person non compos mentis; the words “person” and “whoever” include corporations, companies, associations, firms, partnerships, societies, and joint stock companies, as well as individuals; “officer” includes any person authorized by law to perform the duties of the office; “signature” or “subscription” includes a mark when the person making the same intended it as such; “oath” includes affirmation, and “sworn” includes affirmed; “writing” includes printing and typewriting and reproductions of visual symbols by photographing, multigraphing, mimeographing, manifolding, or otherwise.