My boss uses the term "portal" for the project I work on all the time.
To me, the word makes me think of Yahoo in the late 90s. Does the word "portal" have old-school connotations, or is it just me? Do you think it's ok to use it or will it drag our client's perception of the product down into the middle-ages?
I don't think it's obsolete. In my experience, it's usually used to describe a particular type of website. Usually, a "portal" site is one that is not available to the public - you need to sign in to it, and it's also not always possible for the general public to even request access. I'm thinking banks, insurance companies, schools, etc... often refer to the websites that provide service exclusively to their customers/clients as "portals". This is how I am most familiar with the term because I have worked on a few projects that fit this definition and were definitely called portals by all involved. However, not all of the websites were called portals.
This definition is not always restricted to exclusive access, because I know some websites, like Yahoo!, like to call their landing page a "portal" to everything that is available via Yahoo!, and anyone can access the content of this portal. So a "portal" could be a site that is simply an entry point to other services provdided by the provider of the portal. The other services and portal could all be a part of the same, web application, or they could all be separate applications.
Maybe you're boss is using the term wrong and applying it to sites that don't fit any definition of "portal"?
"Portal" has two meanings in this case. First, it can mean a sort of aggregation site (like your Yahoo example). Second, it can mean a sort of site architecture, where the page is kind of a formatting container which takes data from "portlets" (or the equivalent). It's often used to create dashboard-type sites where information from several different systems can be collected (a lot of Sharepoint sites are built like this).
Original meaning of "web portal" was coined in mid-90's based on analogy, that users would enter the virtual world (the web) stepping through the portal. Sounds totally cheesy nowadays, but that was the marketese of the 90's.
Basically that would be kind of site, which user would set as default in the browser and use it to navigate to other sites. At that time most portals would be aggregating all kind of content, and also would provide content directories (one of the last directories to be still alive is ODP (aka DMOZ)).
The problem with directories was that with the Web rapidly growing they couldn't keep up. They've been made obsolete by generic web search.
So really, what killed portals is Google. But on the other hand, google.com kind of fits wider definition of portal. It is a page that many users have set as their default page in the browser, and it is page that they use to navigate to other pages.
Other meanings - by late 1990's "portal" became most abused buzzword, so any startup building any kind of web site would call it "a portal" just to get piece of dot-com rush (which later was known as dot-com bubble).
Portal can have old-school connotations though it is important to remember the context of the term. For example, I remember in a couple of video games where there would be portals as a way to move a character around in a fictional world. In my work environment, various departments will have "portal sites" that is how they communicate within the company that does make sense.
The key point is to make sure you understand all the nuances that may be meant within someone saying a portal as while there are search engine portals, there are also a whole lot of other ways to use the term that may or may not have been intended. Ambiguous language can be annoying but this is why there are clarification questions to nail down to the context so that there isn't a misunderstanding.
There is a webmasters.SE, we're programmers and our sites are notoriously outdated, although not so much as the postdoc crew.
Do you mean, A) does the 'word' portal have any meaning today, or B) should you still design your sites around web portals?
The answer to A) is yeah, it's not an antiquated word, it's an antiquated technique.
The answer to B) is no, See A. (as in antiquated)
This is almost the goal of Facebook, so I wouldn't say the concept is obsolete. The term, perhaps. Just like in the late 90's many products were the "__ 2000". It's a marketing term, and comes and goes in the cycles of that trade (next to go/going... Web 2.0 and a bit after that the practice of labeling everything under the sun "social").
