Source code refers to the programming language one uses to write a program. There are hundreds, if not thousands, of programming languages, including C++, Java, and Unix. Often people refer to source code of websites, which means programming conducted in HTML and possibly Java.
In most Internet browsers, one has the option of viewing an Internet page in source code format. This is actually quite helpful for people learning to program in HTML, since they can use it to figure out how to do a table, construct a list, or make a hyperlink. People often use the programming from websites they like to achieve a similar look to a page they are constructing.
While it is fine to use source code to create different things like tables, columns or separations on a website, it is important not to copy graphics that come from other websites, unless they are free to use. This would come under the heading of Internet plagiarism, and could lead to problems for one’s new website.
In HTML, source code can be differentiated from text and pictures, as code instructions will almost always initiate in < > format. If one views the source code of this page, one will note that the above bold word of "views" is surrounded by code. This is because HTML requires this information to present the word in bold format.
When viewing the source code, it may be noted that all hyperlinks are surrounded by specific instructions. Each paragraph begins and ends with <p>, meaning "paragraph." In order to italicize a word, the word is put between <em> and </em>.
Often the "/" is taken to mean one is ending a particular set of instructions.
Note that many word processing programs may not be appropriate for writing HTML. Many do not recognize some of the symbols used, like quotation marks. Often one can obtain free programs, which allow the user to write source code that is easy to upload to an Internet site. As well, many website programming programs exist for purchase and may eliminate the need to code.