I can't believe the amount of difficulty I've had finding the Bible app feature I wanted for my Android phone.
Don't get me wrong... there are a BAZILLION Bible apps out there. The #1 app I would recommend to any Android user is the YouVersion app (actually, for pretty much any platform YouVersion has an app, and they are all terrific!) If you don't have a Bible app on your phone, just get YouVersion. Just click over and download it. Now. It's totally a no-brainer. I love YouVersion, but it doesn't really have one of the things I wanted: to be able to look up original-language definitions for individual words. Basically, I wanted to be able to click on something and see the Strong's Concordance definition. YouVersion is focuses on getting people to read devotionally, not really on drilling deeper with Word Studies and such... not a criticism, just an observation. I still have YouVersion on my phone. I still use it quite often. And I still highly recommend it; it's one of the first things I install on any new phone. But it didn't have the one function I wanted.
So I looked further. I have invested some time and money into modules for my Logos desktop software, so I decided to try out their app, figuring that since Logos is designed for serious study, it would probably have by dream feature. The Logos Bible app does link up to most of the modules I've purchased for my desktop version (though not all of them), and it does have some pretty nice study features for a mobile app. It also has a split-screen function so you can view two books (two different translations, a Bible and Study Bible Notes, a Bible and a Bible Dictionary, etc.) and I use that constantly. And it has some Greek/Hebrew language functions, but strangely enough, trying to click an English word and find out what the original-language word means is a little bit hit or miss. I still have it installed, and I use it quite frequently in church, but it didn't have that one key thing I wanted: click the word, read the definition. (By the way, there are some free Logos modules, but you'll get access to a lot more translations for free with YouVersion than with Logos.)
There are mobile versions of a lot of the Bible Web sites out there, too, and quite good ones: Bible Gateway, My Study Bible, and even YouVersion have standout mobile sites, and I bookmarked all of them. The problem with those is that the cell data reception inside my church is pretty awful, and at the time they didn't have WiFi for use by the congregation, so using those in church wasn't going to happen. It needed to be an app with offline versions, like YouVersion or Logos.
So I started trying out apps that were being developed by some of the other Bible Web sites I was familiar with. Bible Gateway released an app which is pretty good. Bible.is has an app which incorporates video clips from "The Jesus Film," which is sort of an unusual feature. eBible.com took an interesting tack with their app: you actually speak the Bible reference you want to look up, and it reads it back to you audibly! I tried all of those, and even installed the plain-vanilla ESV only app, mainly just because I'm a big ESV fan and wanted to take a look at it. They all had good points and bad points, but none of them had what I wanted: direct links from the Bible text to Strong's numbers.
A very recent entry into the fray deserves a mention: the Faithlife Study Bible. This app is actually a whole self-contained Study Bible with several available translations and with study notes that are actually tweaked specifically to match whatever translation you are reading. The notes will actually grow and evolve over time, as readers email in questions and new articles are added. It's a really cool deal, and I like it a lot... but it uses the Logos engine, so still no direct-to-definitions functionality.
Finally I just dug in until I found an app with a screen shot that looked like exactly what I wanted. I installed it, and it works like a charm... not only does it have Strong's definitions, but it also has Thayer's definitions, which are broader in scope than the brief Strong's definitions. The app is called MySword Bible, and the screen shot you see at right shows the KJV translation with the Strong's links inline. It does exactly what I had hoped all those other apps would do, so I use it only for that... I never switch from the KJV+Strong's translation. It's very easy to find a verse (some of the apps listed above are surprisingly hard or slow to navigate, particularly Logos), and if I want to read Strong's/Thayer's definitions, I just click on the Strong's number.
But I didn't get rid of the other apps, no sir! I have MySword installed, but I also have YouVersion, Logos Bible, and Faithlife Study Bible installed. Some church services I'll actually run all of them concurrently, with different translations open in each! That way I can switch between five or six translations very quickly and never lose my place in any of them. (The danger is that you can get so distracted by driving your phone that you forget to listen to the minister... but I digress.) It's incredible the sheer volume of information about the Bible that is accessible from my little $200 cell phone. Sitting in church, I have in my hands the equivalent of a whole bookshelf full of Bible translations and study works. It's funny, though, that it took me over a year to find an app with the one single feature I was looking for!