Final answer:
The word 'however' is used as a transition to indicate contrast and guide readers through a change in the flow of ideas or argument.
Step-by-step explanation:
The word 'however' functions as a transition by indicating a contrast or exception to what has been previously stated. It serves as a signal to the reader that the upcoming sentence or idea will differ from or oppose the thought that was introduced before 'however.' In essence, it prepares the reader for a shift in direction in the argument or narrative.
An example of this transitional use could be, 'The author believed the policy would be effective; however, the results showed otherwise.' This sentence illustrates how 'however' introduces a contrasting idea, thus enhancing the flow of communication.