What constitutes “deferred adjudication”?

In Texas, there are three general types of probations (using the term generically).  The first is pre-trial diversion.  Many courts and DA's offices offer programs whereby if a person completes a program (usually involving some rehab), then they will dismiss the charges after the completion of the program.  This results in an outright dismissal and a defendant can honestly answer that they have never been convicted or placed on deferred adjudication for a crime.  Deferred adjudication is the second type of probation.  In this type, a "finding of guilt" is deferred or held off until the person violates their conditions of probation.  If a defendant never violates, they can be discharged and the charges can eventually be dismissed, but the event will still appear on their criminal history as a deferred.  The advantage of this type of case is that a defendant is not "finally convicted."  The third type of probation is a strait probation.  Here the defendant is found guilty and is convicted, but his sentence is suspended (it's held off), until if/when the defendant violates a term of their probation.  If a defendant completes their probation, they will still be considered convicted of a felony offense for the purposes of many rights (like the right to vote and carry a firearm), but they won't be considered to have a conviction for enhancement purposes later.  So... to answer your question, it depends on what the title of your paperwork says.  If it said "Pre-trial diversion" or something similar, you can honestly answer that you have not been convicted or placed on deferred adjudication.  If the title of your paperwork says "Deferred Adjudication" or "Order deferring guilt", then you were placed on a deferred adjudication.  You would need to answer that you were placed on a deferred if it still appears on your record.  If the title of your paperwork says something like "Judgment of Guilt" or "judgment Adjudicating Guilt", then you need to answer that you have been convicted of a crime.  If the titles are not clear, have a criminal law attorney review your paperwork so that you'll know for sure.  With regard to the speeding ticket part of your question, most employers are not all that concerned with traffic tickets, however, you may want to double check so as not to have any issues in the event that you are hired.