Arrange the given words in the sequence in which they occur in the dictionary.

1. Gain

2. Gaiter

3. Gainsay

4. Gaiety

5. Gauge

4,1,3,2,5

The option that represents the correct order of the given words as they would appear in an English dictionary is shown below:

4. Gaiety

1. Gain

3. Gainsay

2. Gaiter

5. Gauge

 Hence, '4,1,3,2,5' is the correct answer.