How do you measure "one inch of water per week"?

I know, I know, probably dumb question. But I just got used to think fl. oz. and gallons without looking too "immersed". So, if for a plant it is recommended "on average one inch of water per week", what does it mean?
Is it a lot? Is it little?

Thank you,
Goofy

From articles I have read, 1" of water per week usually refers to watering certain areas, for instance, a lawn. You can use some sort of bucket, pan, etc., set this in the area you need to water and turn your sprayer on, and measure how long it takes to reach 1" of water in your container, then you will know how long to run your sprayer, etc.

Ok, now I am going to add my dumb question on top of this ;)

If you have a big bucket and a small bucket side by side and you turn the sprinkler on, won't it take longer for the larger bucket to reach 1"? Or is that some kind of trick question?

I ask because the whole concept of knowing how much to water really baffles me, too. Last year I was concerned that I was underwatering my plants, so I watered a lot....and then got a somewhat embarrassing call from the water district basically asking what I was doing with all that water.

Sorry about my dumb answer to a perfectly good question -- what I SHOULD HAVE SAID was buy one of those plastic rain gauges that you can stick in the ground that has the inches marked off -- you can buy them at Lowe's or Home Depot or most hardware stores. That should give you the right measurement!
Noreaster: We get a note from our water department every fall stating that we must have a leak somewhere, however, that doesn't prevent them from charging us for EXTRA WATER over our "limit."

Thank you, JeanK, for both your answers.
So, I assume, it doesn't actually apply if you grow those plants in pots (almost everything I have is potted, no real garden of my own). The landlord's lawn grows just fine without me watering it, and when the rainy season starts, inches or not, it actually grows quite fast.
Noreaster, I understand you. I also thought "Do I water them enough?", especially since they are potted, increasing their water demands. We did not, however, receive any calls... only bills, as JeanK said. Oh, and sometimes my DH complains, since I don't go to bed without checking if any "babies" need their bottle, but he actually likes my flowers and helps me.
Most of the year here we also have a lot of humidity in the air, so it helps me a bit with some of my plants (and kills/sickens others, but that's another story). But I kept wondering about the inch thing... logically thinking, you would say inches measure length, not water volumes. So, I really felt dumb.
Thank you all for your thoughts.
Goofy

In answer to the question about the buckets...the total volume of water that you collect in the large bucket will be greater, but the depth of it in the bucket will be the same and the time it takes to fill it to 1" high will be the same. (assuming the buckets both have straight sides and aren't tapered...anything tapered is going to mess up your measurement).

If you're watering with sprinklers, it's also a good idea to do the bucket (or rain gauge) test in a couple different places relative to the sprinklers, you will likely find that some areas get more water than others.

Since you have pots, it depends on what type, i.e., clay or plastic. The clay pots allow the dirt in the pots to dry out faster than the plastic ones. Actually, most of the time I have found that overwatering kills more plants than underwatering. Lots of plants don't like soggy roots and I have found that the plastic pots really hold the moisture in.

Thank you, Ecrane! Your answer confirms that the term is mostly used for growing garden plants, so I shouldn't worry right now. I might just do the test, just for fun... you know how practice helps theory stick in your brain... and hopefully someday I'll get my dream house with garden and I will really use the inches to measure the water LOL!
Since I've been in Miami, I managed to kill very little because of the watering issues, contrary to the "misterious inch theory". More because of "completely wrong zone", and some because of the air humidity I was talking about (my lavender issue!).
Jean, in the last couple of years, I found out that most of my plants really enjoy the clay pots more, even if this means more frequent watering. I have a few that do great in glazed pots or plastic pots, but these are very thirsty by nature, enjoying the wet soil more.
Since everything you buy seems to come in plastic these days, I usually transfer (repot) in clay pots as soon as I can (it usually involves a new trip to HD with DH...)