-Gram, -Graph, and -Graphy
Not only do our next set of suffixes look similar, but their meanings are very closely related as well.

So, you need to explain that someone needs to record a record using an instrument to record. Now, we aren't talking about your favorite group making a recording. We are talking about a recording in the medical field. The suffixes to explain this can be confusing until you look closer at them like we are going to now. We will use 'electrocardi,' meaning 'electrical activity of the heart,' with each of these suffixes.

The suffix -graphy means 'to record' or 'take a picture.' You will use this suffix when describing the act of recording or taking the picture. Putting this with our example term gives us 'electrocardiography,' meaning 'to record the electrical activity of the heart.'

After you go through the process of recording or taking a picture, a physical printout and/or computer record results. To describe this, you would use the suffix -gram, meaning 'record' or 'picture.' For example, 'electrocardiogram' means 'the record of electrical activity of the heart.'

The last of these suffixes dealing with records and recording is -graph which is the 'instrument used to record or take a picture.' For instance, the electrocardiograph is the instrument used to record the electrical activity of the heart. The distinction with this suffix is that it refers to the machine that will do the recording.

Now, it should be easier to see that the '-graph' is the 'instrument used to record,' '-graphy' is recording or 'to record,' and '-gram' is the result of the recording or the 'record.'