object n. 1. any Lisp datum. ``The function cons creates an object which refers to two other objects.'' 2. (immediately following the name of a type) an object which is of that type, used to emphasize that the object is not just a name for an object of that type but really an element of the type in cases where objects of that type (such as function or class) are commonly referred to by name. ``The function symbol-function takes a function name and returns a function object.''

object-traversing adj. operating in succession on components of an object. ``The operators mapcar, maphash, with-package-iterator and count perform object-traversing operations.''

open adj., v.t. (a file) 1. v.t. to create and return a stream to the file. 2. adj. (of a stream) having been opened[1], but not yet closed.

operator n. 1. a function, macro, or special operator. 2. a symbol that names such a function, macro, or special operator. 3. (in a function special form) the cadr of the function special form, which might be either an operator[2] or a lambda expression. 4. (of a compound form) the car of the compound form, which might be either an operator[2] or a lambda expression, and which is never (setf symbol).

optimize quality n. one of several aspects of a program that might be optimizable by certain compilers. Since optimizing one such quality might conflict with optimizing another, relative priorities for qualities can be established in an optimize declaration. The standardized optimize qualities are compilation-speed (speed of the compilation process), debug (ease of debugging), safety (run-time error checking), space (both code size and run-time space), and speed (of the object code). Implementations may define additional optimize qualities.

optional parameter n. A parameter for which a corresponding positional argument is optional. If the argument is not supplied, a default value is used. See also supplied-p parameter.

ordinary function n. a function that is not a generic function.

ordinary lambda list n. the kind of lambda list used by lambda. See modified lambda list and extended lambda list. ``defun uses an ordinary lambda list.''

otherwise inaccessible part n. (of an object, O1) an object, O2, which would be made inaccessible if O1 were made inaccessible. (Every object is an otherwise inaccessible part of itself.)

output adj. (of a stream) supporting output operations (i.e., being a ``data sink''). An output stream might also be an input stream, in which case it is sometimes called a bidirectional stream. See the function output-stream-p.

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