While Google (GOOG 0.74%) (GOOGL 0.70%) and Amazon (AMZN 3.26%) have different primary businesses, the two companies have increasingly encroached on each other's territory. Amazon created a platform to sell ads, which is the principle way the search giant makes money, and now, Google is preparing to make an aggressive move into retail.

The company won't be taking on an inventory of goods as Amazon does in warehouses around the country and world. Instead Google has partnered with a number of retailers in deals aimed at winning business away from Amazon.com, and the initiatives look like direct answers to the e-tail leader's efforts.

Amazon may have a huge lead when it comes to selling digitally, but Google has an enormous audience and partners including Target (TGT -0.39%), Kohl's (KSS -0.53%), Staples (SPLS), Toys R Us, Walgreen (WBA -1.77%), and Barnes & Noble (BKS). Google may not be a major player yet, but it's making moves to challenge Amazon and the sheer size of its audience makes it an immediate challenger.

The buy button
Amazon has always been all about shopping while Google, a search engine first, has been about discovery. It's possible to find items for sale on Google -- in many cases they come up in a "shop" box on the right side of search results, but users must still click on the choices, which takes them to a partner site.

It's not an overly complicated experience, but it's harder than Amazon's one-click purchase option and a little unwieldy compared to normal Amazon.com checkout.

To remedy the matter and make buying from Google's retail partners easier, the company has approached retailers about adding a buy button that would approximate the functionality of Amazon's one-click option, The Wall Street Journal reported, adding that several retailers were cool to the idea.

Google would not ship or handle any of the items, it would simply be streamlining the ordering process, which should increase sales for its partners and lure more shoppers to buy.

Two-day shipping
One of Amazon's core methods of keeping a loyal customer base is offering unlimited two-day shipping to members of its Prime service, who pay $99 annually for the service  (which includes a number of other perks including free video and music). Google is looking at working with its partners to offer a similar two-day shipping offer -- perhaps for a lower price.

"The program would resemble ShopRunner, which offers unlimited two-day shipping from retailers including Neiman Marcus Group and Toys "R" Us for a $79 annual fee," The Journal wrote, citing an unnamed person who had been briefed on the plan.

Same-day delivery
While the buy button and two-day shipping are just ideas Google is considering, the company is already competing with Amazon by offering same-day delivery in select markets. Dubbed Google Express, the service offers free, same-day delivery from a wide group of retailers including the ones listed above and many more.

Google Express offers a viable alternative to Amazon's same-day delivery offering and, by partnering with big-name retailers, sometimes offers better merchandise. In October, a year after launching Google Express, the company boasted 37 retailers and said the service was available to 7 million people in the areas where it is available.

Google is making a run
While Amazon has been the dominant online retailer, Google.com is the most visited website in the U.S. and the world. By making it easier to buy on its website and offering convenient delivery, the search giant could leverage its enormous audience and become a retail player.

In addition, the company can do so without the inventory expense Amazon incurs. If Google can make this all happen -- and it still needs partner buy-in for that to occur -- it could cut into Amazon's business.