1) In computers, a BLOB (binary large object), pronounced BLAHB and sometimes spelled in all lower case, is a large file, typically an image or sound file, that must be handled (for example, uploaded, downloaded, or stored in a database) in a special way because of its size. According to Eric Raymond, the main idea about a BLOB is that the handler of the file (for example, the database manager) has no way of understanding the file in order to figure out how to deal with it - it might as well be a large piece of coal, but there it is and now what? Other sources emphasize that the term was coined to refer to big data objects and to connote the problems they sometimes present in handling them. One application that deals with BLOBs is the database storage of large multimedia objects, such as films and television programs.
2) In computer graphics, a blob (lower case) is a visual object that, according to one user of the Persistence of Vision ray tracer, a freeware image creation tool, has "an interesting shape type" that is flexible and amenable to animation.
3) In general, a blob is an amorphous and undefinable object. There are blobs in astronomy as well as in unidentified flying object studies. There was a science-fiction movie called "The Blob."