object: Something a variable can refer to. For now, you can use “object” and “value” interchangeably.
sequence: An ordered set; that is, a set of values where each value is identiﬁed by an integer index.
item: One of the values in a sequence.
index: An integer value used to select an item in a sequence, such as a character in a string.
slice: A part of a string speciﬁed by a range of indices.
empty string: A string with no characters and length 0, represented by two quotation marks.
immutable: The property of a sequence whose items cannot be assigned.
traverse: To iterate through the items in a sequence, performing a similar operation on each.
search: A pattern of traversal that stops when it ﬁnds what it is looking for.
counter: A variable used to count something, usually initialized to zero and then incre mented.
method: A function that is associated with an object and called using dot notation.
invocation: A statement that calls a method.