If one thing includes another thing, it has the other thing as one of its parts.
If someone or something is included in a large group, system, or area, they become a part of it or are considered a part of it.
if something such as a bag, box, or place contains something, that thing is inside it.
if a document, book, speech etc contains something, that thing is included in it.
if a substance contains something, that thing is part of it.